(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Produce an example in the category in which objects are open sets inand morphisms are continuous maps, to illustrate that Hom sets need not be abelian groups in this category.R^{2}

3. The attempt at a solution

I'm missing something stupid here. I'd think that I was looking for two open setsA,Binsuch that, for someR^{2}f,ginHom(A,B), fg != gf. No? I have no clue what the group operation is supposed to be.

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# Prove this is not a preadditive category?

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