diff --git a/theorems/T000534.md b/theorems/T000534.md index ceb657ef3..6d9b20a97 100644 --- a/theorems/T000534.md +++ b/theorems/T000534.md @@ -2,10 +2,16 @@ uid: T000534 if: and: - - P000016: true + - P000019: true - P000112: true then: P000053: true --- -A compact space does not have a strictly coarser $T_2$ topology. +Let $f \colon X \to Y$ be a continuous bijection from a {P19} space $X$ to a {P53} space $Y$. + +Let $A \subseteq X$ be closed. +Since closed subspaces and continuous images of a {P19} space are {P19}, $f(A)$ is {P19}. +Since $Y$ is {P53}, it is {P103} [(Explore)](https://topology.pi-base.org/spaces?q=Metrizable+%2B+%7EStrongly+KC), and hence $f(A)$ is closed in $Y$. + +Therefore, $f$ is a closed map and $f$ is a homeomorphism, which implies $X$ itself is {P53}.