Просмотр кода страницы K-Wide distance

'''<math>k</math>-Wide distance''' --- <math>k</math>-широкое расстояние. 

For two distinct vertices <math>x,y \in V(G)</math>,  the ''' <math>k</math>-wide distance'''
<math>d_{k}(x,y)</math> between <math>x</math> and <math>y</math> is the minimum integer <math>l</math> such  that
there exist  <math>k</math>  vertex-disjoint  <math>(x,y)</math>-chains whose lengths are at
most <math>l</math>. We define <math>d_{k}(x,x) = 0.</math>