Vizing's conjecture

Vizing's conjecture --- гипотеза Визинга.

In 1963 V.Vizing conjectured that

[math]\displaystyle{ \gamma(G)\gamma(H) \leq \gamma(G \Box H) }[/math]

for all graphs [math]\displaystyle{ G }[/math] and [math]\displaystyle{ H }[/math], where [math]\displaystyle{ \gamma(G) }[/math] denotes the domination number of [math]\displaystyle{ G }[/math] and [math]\displaystyle{ G \Box H }[/math] is the Cartesian product of [math]\displaystyle{ G }[/math] and [math]\displaystyle{ H }[/math].