Disjunctive sum
From Encyclopedia of Mathematics
disjunct sum, of topological spaces ,
The space , where each is a copy of and for , while the topology on is defined by the condition that a set is open in if and only if its intersection with each is open. In other words, each is open and closed in .
Comments
The space is also called the discrete sum or the discrete union of the .
How to Cite This Entry:
Disjunctive sum. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Disjunctive_sum&oldid=46744
Disjunctive sum. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Disjunctive_sum&oldid=46744
This article was adapted from an original article by A.A. Mal'tsev (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article