Topological invariant
= Topological invariant
A topological invariant is a property or mathematical object preserved by <homeomorphisms> of <topological spaces>. <Connectedness> and <compactness> are examples. The <fundamental group> is an invariant up to <group isomorphism>; it is also preserved up to <isomorphism> by <homotopy equivalence>, a stronger invariance property which does not hold for every topological invariant.