nLab Strøm's theorem

Strøm’s theorem

Let $(X,A)$ and $(Y,B)$ be NDR-pairs. Their product in the category of topological pairs

$(X\times Y,X\times B\cup A\times Y)$

is also an NDR-pair.

Revised on December 3, 2009 23:12:57 by Toby Bartels (173.60.119.197)