<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE article  PUBLIC "-//NLM//DTD Journal Publishing DTD v3.0 20080202//EN" "http://dtd.nlm.nih.gov/publishing/3.0/journalpublishing3.dtd"><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" dtd-version="3.0" xml:lang="en" article-type="research article"><front><journal-meta><journal-id journal-id-type="publisher-id">JAMP</journal-id><journal-title-group><journal-title>Journal of Applied Mathematics and Physics</journal-title></journal-title-group><issn pub-type="epub">2327-4352</issn><publisher><publisher-name>Scientific Research Publishing</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.4236/jamp.2015.310153</article-id><article-id pub-id-type="publisher-id">JAMP-60586</article-id><article-categories><subj-group subj-group-type="heading"><subject>Articles</subject></subj-group><subj-group subj-group-type="Discipline-v2"><subject>Physics&amp;Mathematics</subject></subj-group></article-categories><title-group><article-title>
 
 
  Qualitative Properties and Numerical Solution of the Kolmogorov-Fisher Type Biological Population Task with Double Nonlinear Diffusion
 
</article-title></title-group><contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>ildora</surname><given-names>Kabulovna Muhamediyeva</given-names></name><xref ref-type="aff" rid="aff1"><sub>1</sub></xref><xref ref-type="corresp" rid="cor1"><sup>*</sup></xref></contrib></contrib-group><aff id="aff1"><label>1</label><addr-line>National University of Uzbekistan, Tashkent, Uzbekistan</addr-line></aff><author-notes><corresp id="cor1">* E-mail:<email>matematichka@inbox.ru</email></corresp></author-notes><pub-date pub-type="epub"><day>20</day><month>10</month><year>2015</year></pub-date><volume>03</volume><issue>10</issue><fpage>1249</fpage><lpage>1255</lpage><history><date date-type="received"><day>24</day>	<month>July</month>	<year>2015</year></date><date date-type="rev-recd"><day>accepted</day>	<month>23</month>	<year>October</year>	</date><date date-type="accepted"><day>26</day>	<month>October</month>	<year>2015</year></date></history><permissions><copyright-statement>&#169; Copyright  2014 by authors and Scientific Research Publishing Inc. </copyright-statement><copyright-year>2014</copyright-year><license><license-p>This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/</license-p></license></permissions><abstract><p>
 
 
  In the present work we study the global solvability of the Kolmogorov-Fisher type biological population task with double nonlinear diffusion and qualitative properties of the solution of the task based on the self-similar analysis. In additional, in this paper we consider the model of two competing population with dual nonlinear cross-diffusion.
 
</p></abstract><kwd-group><kwd>Double Nonlinearity</kwd><kwd> Cross-Diffusion</kwd><kwd> Biological Population</kwd><kwd> A Parabolic System of Quasilinear Equations</kwd><kwd> Convective Heat Transfer</kwd><kwd> Numerical Solution</kwd><kwd> Iterative Process</kwd><kwd> Self-Similar Solutions</kwd></kwd-group></article-meta></front><body><sec id="s1"><title>1. Introduction</title><p>Let’s consider in the domain <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x5.png" xlink:type="simple"/></inline-formula> parabolic system of two quasilinear equations of reaction-diffusion with double nonlinear diffusion</p><disp-formula id="scirp.60586-formula1353"><label>(1)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/4-1720344x6.png"  xlink:type="simple"/></disp-formula><disp-formula id="scirp.60586-formula1354"><graphic  xlink:href="http://html.scirp.org/file/4-1720344x7.png"  xlink:type="simple"/></disp-formula><p>which describes the process of biological populations of the Kolmogorov-Fisher in two-component nonlinear medium, the diffusion coefficient which is equal to<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x8.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x9.png" xlink:type="simple"/></inline-formula>, where <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x10.png" xlink:type="simple"/></inline-formula></p><p>are positive real numbers, and<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x11.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x12.png" xlink:type="simple"/></inline-formula>are sought solution .</p><p>Below we investigate the qualitative properties of the considered problem by constructing self-similar system of equations for (1).</p></sec><sec id="s2"><title>2. Self-Similar System of Equations</title><p>Self-similar system of equations we will construct by the method of nonlinear splitting [<xref ref-type="bibr" rid="scirp.60586-ref1">1</xref>] - [<xref ref-type="bibr" rid="scirp.60586-ref3">3</xref>] .</p><p>Substitution in (1)</p><disp-formula id="scirp.60586-formula1355"><graphic  xlink:href="http://html.scirp.org/file/4-1720344x13.png"  xlink:type="simple"/></disp-formula><p>lead (1) to the form:</p><disp-formula id="scirp.60586-formula1356"><label>(2)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/4-1720344x14.png"  xlink:type="simple"/></disp-formula><disp-formula id="scirp.60586-formula1357"><graphic  xlink:href="http://html.scirp.org/file/4-1720344x15.png"  xlink:type="simple"/></disp-formula><p>Choosing</p><p><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x16.png" xlink:type="simple"/></inline-formula>,</p><p>we get the following system of equations:</p><disp-formula id="scirp.60586-formula1358"><label>(3)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/4-1720344x17.png"  xlink:type="simple"/></disp-formula><p>where</p><p><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x18.png" xlink:type="simple"/></inline-formula>,</p><p><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x20.png" xlink:type="simple"/></inline-formula>,</p><p>For the purpose of obtaining self-similar system for the system of Equation (3) we find first the solution of a system of ordinary differential equations [<xref ref-type="bibr" rid="scirp.60586-ref4">4</xref>] - [<xref ref-type="bibr" rid="scirp.60586-ref7">7</xref>]</p><disp-formula id="scirp.60586-formula1359"><graphic  xlink:href="http://html.scirp.org/file/4-1720344x22.png"  xlink:type="simple"/></disp-formula><p>in the form</p><disp-formula id="scirp.60586-formula1360"><graphic  xlink:href="http://html.scirp.org/file/4-1720344x23.png"  xlink:type="simple"/></disp-formula><p>where</p><disp-formula id="scirp.60586-formula1361"><graphic  xlink:href="http://html.scirp.org/file/4-1720344x24.png"  xlink:type="simple"/></disp-formula><p>And then the solution of system (3) is sought in the form</p><disp-formula id="scirp.60586-formula1362"><label>(4)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/4-1720344x25.png"  xlink:type="simple"/></disp-formula><p>and <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x26.png" xlink:type="simple"/></inline-formula> is selected so</p><disp-formula id="scirp.60586-formula1363"><graphic  xlink:href="http://html.scirp.org/file/4-1720344x27.png"  xlink:type="simple"/></disp-formula><p>if<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x28.png" xlink:type="simple"/></inline-formula>.</p><p>Then for <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x29.png" xlink:type="simple"/></inline-formula> we get the system of equations</p><disp-formula id="scirp.60586-formula1364"><label>(5)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/4-1720344x30.png"  xlink:type="simple"/></disp-formula><p>where</p><disp-formula id="scirp.60586-formula1365"><label>(6)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/4-1720344x31.png"  xlink:type="simple"/></disp-formula><p>Consider the self-similar solution of system (5) of the form</p><disp-formula id="scirp.60586-formula1366"><label>(7)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/4-1720344x32.png"  xlink:type="simple"/></disp-formula><p>Then substituting (7) into (5) with respect to <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x33.png" xlink:type="simple"/></inline-formula> we get the following system of nonlinear degenerate self-similar equations:</p><disp-formula id="scirp.60586-formula1367"><label>(8)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/4-1720344x34.png"  xlink:type="simple"/></disp-formula><p>where<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x35.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x35.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x36.png" xlink:type="simple"/></inline-formula>Let’s build an upper solutions for system (8).</p></sec><sec id="s3"><title>3. Construction an Upper Solution</title><p>If</p><p><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x37.png" xlink:type="simple"/></inline-formula>, , ,</p><p>Equation (8) has a local solution of the form</p><disp-formula id="scirp.60586-formula1368"><graphic  xlink:href="http://html.scirp.org/file/4-1720344x40.png"  xlink:type="simple"/></disp-formula><p>where<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x41.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x41.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x42.png" xlink:type="simple"/></inline-formula>,</p><disp-formula id="scirp.60586-formula1369"><graphic  xlink:href="http://html.scirp.org/file/4-1720344x43.png"  xlink:type="simple"/></disp-formula><p>Then in the domain Q according to the comparison principle of solutions [<xref ref-type="bibr" rid="scirp.60586-ref1">1</xref>] [<xref ref-type="bibr" rid="scirp.60586-ref8">8</xref>] we get</p><p>Theorem 1. Let <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x44.png" xlink:type="simple"/></inline-formula> Then the solution of the task (1) in the domain Q takes place an estimation</p><disp-formula id="scirp.60586-formula1370"><graphic  xlink:href="http://html.scirp.org/file/4-1720344x46.png"  xlink:type="simple"/></disp-formula><p>where<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x47.png" xlink:type="simple"/></inline-formula>―above-defined functions.</p><p>Note that the solution of system (1) when <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x48.png" xlink:type="simple"/></inline-formula> has the following representation in the</p><p><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x49.png" xlink:type="simple"/></inline-formula>.</p><p>where<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x50.png" xlink:type="simple"/></inline-formula>―Beta Euler function [<xref ref-type="bibr" rid="scirp.60586-ref9">9</xref>] .</p><p>It is proved that this view is self-similar asymptotics of solutions of systems (1).</p><disp-formula id="scirp.60586-formula1371"><graphic  xlink:href="http://html.scirp.org/file/4-1720344x51.png"  xlink:type="simple"/></disp-formula><p>Thence</p><disp-formula id="scirp.60586-formula1372"><graphic  xlink:href="http://html.scirp.org/file/4-1720344x52.png"  xlink:type="simple"/></disp-formula><p><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x53.png" xlink:type="simple"/></inline-formula>.</p><p>Carried out computational experiments and numerical results are obtained (see <xref ref-type="table" rid="table1">Table 1</xref>, <xref ref-type="table" rid="table2">Table 2</xref>).</p></sec><sec id="s4"><title>4. Conclusion</title><p>Thus, it is assumed that the possibility of adequate study of nonlinear equations, biological populations with double nonlinearity based on the method of nonlinear splitting and numerical study of nonlinear processes described by equations with double nonlinearity and analysis of results on the basis of the estimates of the solutions gives a comprehensive picture of the process of multicomponent competing systems of biological populations.</p></sec><sec id="s5"><title>5. Results</title><disp-formula id="scirp.60586-formula1373"><graphic  xlink:href="http://html.scirp.org/file/4-1720344x54.png"  xlink:type="simple"/></disp-formula><table-wrap id="table1" ><label><xref ref-type="table" rid="table1">Table 1</xref></label><caption><title> Numerical results in the case of fast diffusion</title></caption><table><tbody><thead><tr><th align="center" valign="middle" >Parameter values</th><th align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x55.png" xlink:type="simple"/></inline-formula> <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x56.png" xlink:type="simple"/></inline-formula></th><th align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x57.png" xlink:type="simple"/></inline-formula> <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x58.png" xlink:type="simple"/></inline-formula></th><th align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x59.png" xlink:type="simple"/></inline-formula> <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x60.png" xlink:type="simple"/></inline-formula></th><th align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x61.png" xlink:type="simple"/></inline-formula> <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x62.png" xlink:type="simple"/></inline-formula></th><th align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x63.png" xlink:type="simple"/></inline-formula> <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x64.png" xlink:type="simple"/></inline-formula></th></tr></thead><tr><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x65.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x66.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x67.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x68.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x69.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x70.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x71.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x72.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x73.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x74.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x75.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x76.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x77.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x78.png" xlink:type="simple"/></inline-formula></td></tr><tr><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x79.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x80.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x81.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x82.png" xlink:type="simple"/></inline-formula> <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x83.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x84.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x85.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x86.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x87.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x88.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x89.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x90.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x91.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x92.png" xlink:type="simple"/></inline-formula></td></tr><tr><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x93.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x94.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x95.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x96.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x97.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x98.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x99.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x100.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x101.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x102.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x103.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x104.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x105.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x106.png" xlink:type="simple"/></inline-formula></td></tr><tr><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x107.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x108.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x109.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x110.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x111.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x112.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x113.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x114.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x115.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x116.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x117.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x118.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x119.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x120.png" xlink:type="simple"/></inline-formula></td></tr><tr><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x121.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x122.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x123.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x124.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x125.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x126.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x127.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x128.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x129.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x130.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x131.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x132.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x133.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x134.png" xlink:type="simple"/></inline-formula></td></tr></tbody></table></table-wrap><table-wrap id="table2" ><label><xref ref-type="table" rid="table2">Table 2</xref></label><caption><title> Numerical results in the case of slow diffusion</title></caption><table><tbody><thead><tr><th align="center" valign="middle" >Parameter values</th><th align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x135.png" xlink:type="simple"/></inline-formula> <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x136.png" xlink:type="simple"/></inline-formula></th><th align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x137.png" xlink:type="simple"/></inline-formula> <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x138.png" xlink:type="simple"/></inline-formula></th><th align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x139.png" xlink:type="simple"/></inline-formula> <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x140.png" xlink:type="simple"/></inline-formula></th><th align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x141.png" xlink:type="simple"/></inline-formula> <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x142.png" xlink:type="simple"/></inline-formula></th><th align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x143.png" xlink:type="simple"/></inline-formula> <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x144.png" xlink:type="simple"/></inline-formula></th></tr></thead><tr><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x145.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x146.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x147.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x148.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x149.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x150.png" xlink:type="simple"/></inline-formula> <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x151.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x152.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x153.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x154.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x155.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x156.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x157.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x158.png" xlink:type="simple"/></inline-formula></td></tr><tr><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x159.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x160.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x161.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x162.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x163.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x164.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x165.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x166.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x167.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x168.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x169.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x170.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x171.png" xlink:type="simple"/></inline-formula></td></tr><tr><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x172.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x173.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x174.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x175.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x176.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x177.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x178.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x179.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x180.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x181.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x182.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x183.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x184.png" xlink:type="simple"/></inline-formula></td><td align="center" valign="middle" ><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x185.png" xlink:type="simple"/></inline-formula></td></tr></tbody></table></table-wrap><p>1) Fast diffusion is shown in <xref ref-type="table" rid="table1">Table 1</xref>. As an initial approximation it is necessary to take:</p><p><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x186.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x186.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x187.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x186.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x187.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x188.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x186.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x187.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x188.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x189.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x186.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x187.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x188.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x189.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x190.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x186.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x187.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x188.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x189.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x190.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x191.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x186.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x187.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x188.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x189.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x190.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x191.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x192.png" xlink:type="simple"/></inline-formula></p><p>Parameter values must be <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x193.png" xlink:type="simple"/></inline-formula> Constant a is determined from the condition<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x193.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x194.png" xlink:type="simple"/></inline-formula>,<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x193.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x194.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x195.png" xlink:type="simple"/></inline-formula>: <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x193.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x194.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x195.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x196.png" xlink:type="simple"/></inline-formula></p><p>2) Slow diffusion is shown in <xref ref-type="table" rid="table2">Table 2</xref>. As an initial approximation it is necessary to take:</p><p><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x197.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x197.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x198.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x197.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x198.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x199.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x197.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x198.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x199.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x200.png" xlink:type="simple"/></inline-formula>, т, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x197.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x198.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x199.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x200.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x201.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x197.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x198.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x199.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x200.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x201.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x202.png" xlink:type="simple"/></inline-formula></p><p>Parameter values must be<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720344x203.png" xlink:type="simple"/></inline-formula>. Constant a is determined from the condition</p><disp-formula id="scirp.60586-formula1374"><graphic  xlink:href="http://html.scirp.org/file/4-1720344x204.png"  xlink:type="simple"/></disp-formula></sec><sec id="s6"><title>Cite this paper</title><p>Dildora KabulovnaMuhamediyeva, (2015) Qualitative Properties and Numerical Solution of the Kolmogorov-Fisher Type Biological Population Task with Double Nonlinear Diffusion. Journal of Applied Mathematics and Physics,03,1249-1255. doi: 10.4236/jamp.2015.310153</p></sec></body><back><ref-list><title>References</title><ref id="scirp.60586-ref1"><label>1</label><mixed-citation publication-type="other" xlink:type="simple">Aripov, M. (1988) Method Reference Equations for the Solution of Nonlinear Boundary Value Problems. Fan, Tashkent, 137.</mixed-citation></ref><ref id="scirp.60586-ref2"><label>2</label><mixed-citation publication-type="other" xlink:type="simple">Belotelov, N.V. and Lobanov, A.I. (1997) Population Model with Nonlinear Diffusion. Mathematic Modeling, 12, 43-56.</mixed-citation></ref><ref id="scirp.60586-ref3"><label>3</label><mixed-citation publication-type="other" xlink:type="simple">Volterra, V. (1976) The Mathematical Theory of the Struggle for Existence. Science, Moscow, 288.</mixed-citation></ref><ref id="scirp.60586-ref4"><label>4</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Gause</surname><given-names> G.F. </given-names></name>,<etal>et al</etal>. (<year>1934</year>)<article-title>About the Processes of Destruction of One Species by Another in the Populations of Ciliates</article-title><source> Zoological Journal</source><volume> 1</volume>,<fpage> 16</fpage>-<lpage>27</lpage>.<pub-id pub-id-type="doi"></pub-id></mixed-citation></ref><ref id="scirp.60586-ref5"><label>5</label><mixed-citation publication-type="other" xlink:type="simple">Aripov, M. and Muhammadiev, J. (1999) Asymptotic Behaviour of Automodel Solutions for One System of Quasilinear Equations of Parabolic Type. France. Buletin Stiintific-Universitatea din Pitesti, Seria Matematica si Informatica, 19-40.</mixed-citation></ref><ref id="scirp.60586-ref6"><label>6</label><mixed-citation publication-type="other" xlink:type="simple">Aripov, M.M. and Muhamediyeva, D.K. (2013) To the Numerical Modeling of Self-Similar Solutions of Reaction-Diffusion System of the One Task of Biological Population of Kolmogorov-Fisher Type. International Journal of Engineering and Technology, 2, 281-286.</mixed-citation></ref><ref id="scirp.60586-ref7"><label>7</label><mixed-citation publication-type="other" xlink:type="simple">Aripov, M.M. and Muhamedieva, D.K. (2013) Approaches to the Solution of One Problem of Biological Populations. Issues of Computational and Applied Mathematics, 129, 22-31.</mixed-citation></ref><ref id="scirp.60586-ref8"><label>8</label><mixed-citation publication-type="other" xlink:type="simple">Murray, D.J. (1983) Nonlinear Diffusion Equations in Biology. Mir, Moscow, 397.</mixed-citation></ref><ref id="scirp.60586-ref9"><label>9</label><mixed-citation publication-type="other" xlink:type="simple">Huashui, Z. (2010) The Asymptotic Behavior of Solutions for a Class of Doubly Degenerate Nonlinear Parabolic Equations. Journal of Mathematical Analysis and Applications, 370, 1-10. http://dx.doi.org/10.1016/j.jmaa.2010.05.003</mixed-citation></ref></ref-list></back></article>