113
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EJC
2016
10 years 1 months ago
2016
In this paper we prove that there exists an absolute constant c > 0 such that for every natural number k, every non-bipartite 2-connected graph with average degree at least ck ...
107
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EJC
2016
10 years 1 months ago
2016
Abstract. In this note we investigate some matroid minor structure results. In particular, we present sufficient conditions, in terms of triangles, for a matroid to have either U2,...
111
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EJC
2016
10 years 1 months ago
2016
It was conjectured by Hoffmann-Ostenhof that the edge set of every cubic graph can be decomposed into a spanning tree, a matching and a family of cycles. We prove the conjecture ...
105
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EJC
2016
10 years 1 months ago
2016
We study the circulant complex Hadamard matrices of order n whose entries are l-th roots of unity. For n = l prime we prove that the only such matrix, up to equivalence, is the Fou...
100
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EJC
2016
10 years 1 months ago
2016
Szemer´edi’s regularity lemma is a fundamental tool in extremal graph theory, theoretical computer science and combinatorial number theory. Lov´asz and Szegedy [7] gave a Hilb...