Article citationsMore>>

Hoffman, D.G., Lindner, C.C., Sharry, M.J. and Street, A.P. (1996) Maximum Packings of K_n with Copies of K₄ − e. Aequationes Mathematicae, 51, 247-269.
https://doi.org/10.1007/bf01833281

has been cited by the following article:

• TITLE: K4 − e Designs on Complete Graphs with a Hole When 5 Divides the Order

  AUTHORS: Roxanne Back

  KEYWORDS: Graph Decomposition, Combinatorial Design, Complete Graph with a Hole, Difference Methods, 1-Factorization

  JOURNAL NAME: Open Journal of Discrete Mathematics, Vol.16 No.4, September 2, 2026

  ABSTRACT: In a companion paper, we settled the existence of K4 − e designs on Kd + v for even d with v = 2(d − 1) − 5a, treating the cases where a is even and odd separately. In this paper, we complete the full characterization for even d by resolving the remaining case: 5 | d. We first establish non-existence when v = 2d − 3 or v = 2d − 4 via a coloring argument. We then prove existence for all admissible v using a combination of direct constructions, a multipartite design on K10,10,10, and a recursive blowup lemma. Together with our earlier results, this yields a complete necessary and sufficient characterization: a K4 − e design on Kd + v exists when d is even if and only if 5 | d(d + 2v − 1), v ≤ 2(d − 1), and v ≠ 2d − 3, v ≠ 2d − 4.