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Glk (обсуждение | вклад)  (Новая страница: «'''Edge-isoperimetric problem''' --- рёберно-изопериметрическая задача.   Given a graph <math>G = (V,E,\partial)</math> having the ver…»)  | 
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'''Edge-isoperimetric problem'''   | '''Edge-isoperimetric problem''' — рёберно-изопериметрическая задача.    | ||
Given a graph <math>G = (V,E,\partial)</math> having the vertex-set <math>V</math>, edge-set <math>E</math> and boundary-function <math>\partial: \, E \rightarrow  | Given a [[graph]] <math>G = (V,E,\partial)</math> having the vertex-set <math>V</math>, edge-set <math>E</math> and boundary-function <math>\partial: \, E \rightarrow  | ||
\left(\begin{array}{c} V \\ 2 \end{array}\right)</math> which identifies the  | \left(\begin{array}{c} V \\ 2 \end{array}\right)</math> which identifies the  | ||
pair of vertices incident to each edge, we define  | pair of [[vertex|vertices]] [[vertex incident to an edge|incident]] to each [[edge]], we define  | ||
<math>\Theta(S) = \{e \in E: \, \partial(e) = \{v,w\}, v \in S \  | <math>\Theta(S) = \{e \in E: \, \partial(e) = \{v,w\}, v \in S \And w \not \in S\}.</math>  | ||
Then, the '''edge-isoperimetric problem''' is to  | Then, the '''edge-isoperimetric problem''' is to  | ||
minimize <math>|\Theta(S)|</math> over all <math>S \subseteq V</math> such that <math>|S| = k</math>    | minimize <math>|\Theta(S)|</math> over all <math>S \subseteq V</math> such that <math>|S| = k</math>    | ||
for a given <math>k \in Z^{+}</math>.  | for a given <math>k \in Z^{+}</math>.  | ||