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The Reconstruction Conjecture of Ulam asserts that, for $ngeq 3$, every $n$-vertex graph is determined by the multiset of its induced subgraphs with $n-1$ vertices. The conjecture is known to hold for various special classes of graphs but remains wide open. We survey results on the more general conjecture by Kelly from 1957 that for every positive integer $ell$ there exists $M_ell$ (with $M_1=3$) such that when $ngeq M_ell$ every $n$-vertex graph is determined by the multiset of its induced subgraphs with $n-ell$ vertices.
The $(n-ell)$-deck of an $n$-vertex graph is the multiset of subgraphs obtained from it by deleting $ell$ vertices. A family of $n$-vertex graphs is $ell$-recognizable if every graph having the same $(n-ell)$-deck as a graph in the family is also in
ErdH{o}s posed the problem of finding conditions on a graph $G$ that imply the largest number of edges in a triangle-free subgraph is equal to the largest number of edges in a bipartite subgraph. We generalize this problem to general cases. Let $delt
It is an intriguing question to see what kind of information on the structure of an oriented graph $D$ one can obtain if $D$ does not contain a fixed oriented graph $H$ as a subgraph. The related question in the unoriented case has been an active are
Kuhn, Osthus and Taraz showed that for each gamma>0 there exists C such that any n-vertex graph with minimum degree gamma n contains a planar subgraph with at least 2n-C edges. We find the optimum value of C for all gamma<1/2 and sufficiently large n.
For a graph $G$, we associate a family of real symmetric matrices, $mathcal{S}(G)$, where for any $M in mathcal{S}(G)$, the location of the nonzero off-diagonal entries of $M$ are governed by the adjacency structure of $G$. The ordered multiplicity I