Talk:Disjoint union (topology)

Canonical injection
Given $$\varphi_i : X_i \to X\,$$, the image of a point x cannot be a pair (x,i) as the latter is not an element of $$X$$. — Preceding unsigned comment added by 199.7.157.48 (talk) 08:58, 17 September 2015 (UTC)

direct sum?
I thought "direct sum" implies product topology, and not the disjoint union. - Subh83 (talk &#124; contribs) 22:39, 6 March 2012 (UTC)