Theorem
The plane
with the euclidean metric is locally compact.
Proof
A space
is said to be locally compact if, for any
and any neighbourhood
of
there is a compact set
such that![]()
is not compact since it is not bounded.
Let
and let
be a neighbourhood of
Then their exists
such that![]()
![]()
The set
is a closed and bounded subset of
so is compact and![]()
Hence
with the Euclidean metric is locally compact.