A method for constructing test functions for global optimization which utilizes continuous formulations of combinatorial optimization problems is suggested. In particular, global optimization formulations for the maximum independent set, maximum clique and MAX CUT problems on arbitrary graphs are considered, and proofs for some of them are given. A number of sample test functions based on these...

The trace of a family of sets A on a set X is A|X = {A ∩ X : A ∈ A}. If A is a family of k-sets from an n-set such that for any r-subset X the trace A|X does not contain a maximal chain, then how large can A be? Patkós conjectured that, for n sufficiently large, the size of A is at most ( n−k+r−1 r−1 ) . Our aim in this paper is to prove this conjecture.

We prove that the number of minimal transversals (and also the number of maximal independent sets) in a 3-uniform hypergraph with n vertices is at most c, where c ≈ 1.6702. The best known lower bound for this number, due to Tomescu, is ad, where d = 10 1 5 ≈ 1.5849 and a is a constant.

Dynkin’s classification of maximal subalgebras of simple finite dimensional complex Lie algebras is generalized to matrix Lie superalgebras, i.e., the Lie subsuperalgebras of gl(p|q).

We show that for hypergraphs of bounded edge size, the problem of extending a given list of maximal independent sets is NC-reducible to the computation of an arbitrary maximal independent set for an induced sub-hypergraph. The latter problem is known to be in RNC. In particular, our reduction yields an incremental RNC dualization algorithm for hypergraphs of bounded edge size, a problem previou...

The independent domination number of a graph G, denoted i(G), is the minimum cardinality of a maximal independent set of G. A maximal independent set of cardinality i(G) in G we call an i(G)-set. In this paper we provide a constructive characterization of trees G that have two disjoint i(G)-sets. © 2005 Elsevier B.V. All rights reserved.

The n-dimensional hypercube Qn has many maximal independent sets of vertices. We study the cardinality of those maximal independent sets which are balanced , i.e. exactly half of whose vertices have even weight, obtaining both upper and lower bounds for the maximum value. For n ≤ 7 we obtain the exact value. For all odd n, we conjecture that the exact value is 2n−1 − ( n−1 (n−1)/2 ) . We also c...

The independent domination number of a graph G, denoted i(G), is the minimum cardinality of a maximal independent set of G. A maximal independent set of cardinality i(G) in G we call an i(G)-set. The graph G is called i-excellent if every vertex of G belongs to some i(G)-set. We provide a constructive characterization of i-excellent trees. c © 2002 Elsevier Science B.V. All rights reserved.

The trace of a set F on a another set X is F |X = F ∩ X and the trace of a family F of sets on X is FX = {F |X : F ∈ F}. In this note we prove that if a k-uniform family F ⊂ ([n] k ) has the property that for any k-subset X the trace F|X does not contain a maximal chain (a family C0 ⊂ C1 ⊂ ... ⊂ Ck with |Ci| = i), then |F| ≤ ( n−1 k−1 ) . This bound is sharp as shown by {F ∈ ([n] k ) , 1 ∈ F}. ...