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Math 6510 • Differentiable Manifolds

Fall 2007 • Question 15

Prove that \(\mathbb {C}P^3\) and \(S^2\times S^4\) have cell complex structures with isomorphic cellular chain complexes, and therefore \(H^i(\mathbb {C}P^3;\mathbb {Z})\cong H^i(S^2\times S^4;\mathbb {Z})\) for all \(i\). Also prove that cohomology rings \(H^*(\mathbb {C}P^3;\mathbb {Z})\) and \(H^*(S^2\times S^4;\mathbb {Z})\) are not isomorphic. Are \(\mathbb {C}P^3\) and \(S^2\times S^4\) homotopy equivalent? You are allowed to use the standard cell complex structure of spheres and complex projective spaces.

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Prove that \(\mathbb{C}P^3\) and \(S^2\times S^4\) have cell complex structures
with isomorphic cellular chain complexes, and therefore
\(H^i(\mathbb{C}P^3;\Z)\cong H^i(S^2\times S^4;\Z)\) for all \(i\). Also prove that
cohomology rings \(H^*(\mathbb{C}P^3;\Z)\) and \(H^*(S^2\times S^4;\Z)\) are not
isomorphic. Are \(\mathbb{C}P^3\) and \(S^2\times S^4\) homotopy equivalent? You are
allowed to use the standard cell complex structure of spheres and complex
projective spaces.