Neighbourhood
From Encyclopedia of Mathematics
of a point $x$ (of a subset $A$) of a topological space
Any open subset of this space containing the point $x$ (the set $A$). Sometimes a neighbourhood of the point $x$ (the set $A$) is defined as any subset of this topological space containing the point $x$ (the set $A$) in its interior (cf. also Interior of a set).
How to Cite This Entry:
Neighbourhood. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Neighbourhood&oldid=30571
Neighbourhood. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Neighbourhood&oldid=30571
This article was adapted from an original article by B.A. Pasynkov (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article