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Does there exist a simple proof of Universal Coefficient for the case of field coefficients?

For field $F$, we know that $$H^n(X;F)\cong Hom_F(H_n(X;F),F)$$

(Is homology with coefficients in a field isomorphic to cohomology?)

Is there a simplified proof for this special case, that is simpler than the whole proof involving Ext?

Thanks.

yoyostein
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1 Answers1

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If you go through a standard proof, as in Hatcher, you will find a lot of shortcuts when doing things over a field. For instance $$0\to Z_n\to C_n\to B_{n-1}\to0$$ will split, as every exact sequence splits over a field. Dualising exact sequences gives exact sequences, so Hatcher's sequence (vii) will be exact, and no Ext terms are needed.

Angina Seng
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