英和和英

出典:『Wikipedia』 (2010/05/15 03:29 UTC 版)

英語による解説

引用

In graph theory, nowhere-zero flows are a special type of network flow which is related (by duality) to coloring planar graphs. Let G = (V,E) be a directed graph and let M be an abelian group. We say that a map is a flow or an M-flow if the following condition (sometimes called the Kirchoff Rule) is satisfied at every vertex (here we let δ ⁺ (v) denote the set of edges pointing away from v and δ ⁻ (v) the set of edges pointing toward v).