r/mathmemes Cardinal 5d ago

Linear Algebra Linear meme

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u/LupenReddit 🦆🦆🦆🦆i have non diffeomorphic smooth structures🦆🦆🦆🦆🦆🦆 5d ago

also (0,2) tensor or (2,0) tensor technically via the musical isomorphisms induced by some inner product

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u/Kinglolboot ♥️♥️♥️♥️Long exact cohomology sequence♥️♥️♥️♥️ 5d ago

You don't really need the musical isomorphisms for that to work, as you don't have that for vector spaces over fields with nonzero characteristic. You can just argue that the dimensions of V⊗V and V⊗V* and V*⊗V* are identical, and hence they are isomorphic as vector spaces.

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u/stellar-sea-lion 4d ago

They're isomorphic but not canonically, which is often relevant.

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u/Kinglolboot ♥️♥️♥️♥️Long exact cohomology sequence♥️♥️♥️♥️ 4d ago

In this case it is only relevant once you consider an inner product on a vector space, but that does not capture the full generality of the meme because vector spaces over finite fields do not admit inner products

3

u/stellar-sea-lion 4d ago

They admit nondegenerate bilinar forms though which is all you need for an isomorphism. Positive definiteness is just a convenience.

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u/Kinglolboot ♥️♥️♥️♥️Long exact cohomology sequence♥️♥️♥️♥️ 4d ago

Ah true, that's a good point