In classical rook theory there is a fundamental relationship between the rook numbers and the hit numbers relative to any board. In that theory the k-th hit number of a board B can be interpreted as the number of permutations whose intersection with B is of size k. In the case of Ferrers boards ther
Forbidden triples for perfect matchings
โ Scribed by Katsuhiro Ota; Michael D. Plummer;; Akira Saito
- Publisher
- John Wiley and Sons
- Year
- 2011
- Tongue
- English
- Weight
- 117 KB
- Volume
- 67
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
โฆ Synopsis
Let H be a set of connected graphs. A graph is said to be H-free if it does not contain any member of H as an induced subgraph. Plummer and Saito [J Graph Theory 50 (2005), 1-12] and Fujita et al. [J Combin Theory Ser B 96 (2006), 315-324] characterized all H with |H| โค 2 such that every connected H-free graph of sufficiently large even order has a perfect matching. Extending this line of research, we give the characterization in the case of |H| โค 3.
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