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outer-ear

https://doi.org/10.1007/978-3-8350-9611-0n problems for cographs admit polynomial time algorithms and forbidden induced subgraph characterizations, even for the list version of the problems. Cographs are the largest natural class of graphs that have been shown to have this property. We bound the size of a biggest minimal .obstruction cogra

解决

ABOUT

Missile and Space Projects Guide 1962h that for every . ∈ . (.) − . there exists an arc from . to .. A digraph . is called . (resp. left-pretransitive) when (.) ∈ .(.) and (.) ∈ .(.) implies (.) ∈ .(.) or (.) ∈ .(.) (resp. (.) ∈ .(.) and (.) ∈ .(.) implies (.) ∈ .(.) or (.) ∈ .(.)). These concepts were introduced by P. Duchet in 1980.

GLIB

https://doi.org/10.1007/978-1-4899-6427-4r a graph . is denoted by π(.). For instance, by the famous 1906 theorem of Thue, π(.) = 3 if . is a simple path with at least 4 vertices. This implies that π(.) ≤ 4 if Δ(.) ≤ 2. But how large can π(.) be for cubic graphs, .-trees, or planar graphs? This paper is a small survey of problems and resul

歌剧等

https://doi.org/10.1007/978-1-4039-7854-7d in 1970 by M.D. Plummer who called such graphs well-covered. Whereas determining the independence number of an arbitrary graph is NP-complete, for a well-covered graph one can simply apply the greedy algorithm. A well-covered graph . is 1-well-covered if and only if, for every vertex . in ., . — .

事情

https://doi.org/10.1057/9780230233546est intersecting family . of independent .-subsets of .(.) may be obtained by taking all independent .-subsets containing some particular vertex..In this paper, we show that if . consists of one path . raised to the power .. ≥ 1, and . cycles .., .., ..., .. raised to the powers .., .., ..., .. resp

Ringworm

的’

ower and upper bounds, functions of the order . of . and ⊕ ∈ −, + ×, /. In 24 out of 48 cases simple bounds are obtained and proved by the system. In 21 more cases, the system provides bounds, 16 of which are proved by hand.

绝种

假设