Просмотр кода страницы Essential independent set

'''Essential independent set''' --- существенное независимое
множество. 

An independent set <math>Y</math> in <math>G</math> is called an '''essential independent set''' (or '''essential set''' for simplicity), if there is <math>\{y_{1},
y_{2}\} \subseteq Y</math> such that <math>dist(y_{1}, y_{2}) = 2</math>.