Is a homotopically equivalent to a $\Delta$-complex space a $\Delta$-complex

algebraic-topologyhomology-cohomology

I'm going through Hatcher's Algebraic Topology, and after reading the paragraphs on simplicial and singular homology, I was wondering about this :

  1. Singular homology is homotopy invariant, that is, two homotopically equivalent topological spaces $X, Y$ have isomorphic homology groups.
  2. Simplicial and singular homology are equivalent, meaning that for a $\Delta$-complex $X$, there are isomorphisms between $H_n^\Delta(X)$ and $H_n(X)$ for all $n$.

Now, would this mean that, given a $\Delta$-complex $X$, any other topological space $Y$ of the same homotopy equivalence class would inherit a $\Delta$-complex structure, and hence have the same simplicial homology groups as $X$?

Best Answer

Having the same homology and "inheriting" $\Delta$-structure are very vaguely related things.

A simplest counterexample would be a contractible space $Y$ which is not a simplicial/$\Delta$/CW-complex. For example the comb space. Because it is not locally connected.

Homotopy equivalences rarely preserve topological properties.

Related Question