Constructing a covering triangulation by means of a nowhere-zero dual flow
نویسندگان
چکیده
منابع مشابه
Nowhere-zero flow polynomials
In this article we introduce the flow polynomial of a digraph and use it to study nowherezero flows from a commutative algebraic perspective. Using Hilbert’s Nullstellensatz, we establish a relation between nowhere-zero flows and dual flows. For planar graphs this gives a relation between nowhere-zero flows and flows of their planar duals. It also yields an appealing proof that every bridgeless...
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In [J Combin Theory Ser B, 26 (1979), 205–216], Jaeger showed that every graph with 2 edge-disjoint spanning trees admits a nowhere-zero 4-flow. In [J Combin Theory Ser B, 56 (1992), 165–182], Jaeger et al. extended this result by showing that, if A is an abelian group with |A| = 4, then every graph with 2 edgedisjoint spanning trees is A-connected. As graphs with 2 edge-disjoint spanning trees...
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Jensen and Toft [10] conjectured that every 2-edge-connected graph without a K5minor has a nowhere zero 4-flow. Walton and Welsh [24] proved that if a coloopless regular matroid M does not have a minor in {M(K3,3),M(K5)}, then M admits a nowhere zero 4-flow. In this note, we prove that if a coloopless regular matroid M does not have a minor in {M(K5),M(K5)}, then M admits a nowhere zero 4-flow....
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We s(ate the following conjecture and prove it for the case where q is a proper prime power: Let A be a nonsingular n by n matrix over the finite fieM GF~, q~-4, then there exists a vector x in (GFa) ~ such that both x and ~4x have no zero component. In this note we consider-the following conjecture: Conjecture 1. Let A be a nonsingular n by n matrix over the finite field GFa, q~_4, then there ...
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ژورنال
عنوان ژورنال: Journal of Combinatorial Theory, Series B
سال: 1982
ISSN: 0095-8956
DOI: 10.1016/0095-8956(82)90007-7