Regard the \(n\)-simplex \(\Delta ^n\) as a \(\Delta \)-complex in the natural way, with \((n+1)\) vertices and a single \(n\)-simplex. Find all subcomplexes \(X\subset \Delta ^n\) such that \(\operatorname {H}_{n-1}(X)\ne 0\) (with a proof that there are no others).
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Math 6510 • Differentiable Manifolds
Spring 2015 • Question 7