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refactor(Analysis/NormedSpace/Exponential): remove the 𝕂
argument from exp
#8370
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…ditive monoids While many of the lemmas cease to apply, the definitions of sequences and their sums are still perfectly well-behaved in additive monoids; no negation is needed. We could use this to generalize `NormedSpace.exp` such that it works with `NNReal`, but unless leanprover-community/mathlib3#16554 or similar lands and provides a `DivisionSemiring.nnqsmul` field, that would conflict with #8370.
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I'm curious if 𝕂
can be stripped from more of the lemmas, using the fact that any normed algebra is a real normed algebra. But possibly that would interfere with inference in practice?
analyticAt_exp_of_mem_ball x ((expSeries_radius_eq_top 𝕂 𝔸).symm ▸ edist_lt_top _ _) | ||
#align exp_analytic NormedSpace.exp_analytic | ||
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variable (𝕂) |
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Why do we need this? If it's so that we pull in a NormedAlgebra assumption, couldn't we always do that over the reals (since complex normed algebras are real normed algebras)?
[∀ i, NormedAlgebra 𝕂 (𝔸 i)] [∀ i, CompleteSpace (𝔸 i)] (x : ∀ i, 𝔸 i) (i : ι) : | ||
exp 𝕂 x i = exp 𝕂 (x i) := | ||
map_exp _ (Pi.evalRingHom 𝔸 i) (continuous_apply _) x | ||
[∀ i, Algebra ℚ (𝔸 i)] [∀ i, NormedAlgebra 𝕂 (𝔸 i)] [∀ i, CompleteSpace (𝔸 i)] (x : ∀ i, 𝔸 i) |
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Could we switched the normed algebra to be always over the reals, as complex normed algebras are real normed algebras (resp. below)?
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Turns out this could be generalized anyway, #10865
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I think there's a good chance a few of the instance hypotheses can be removed (in particular, anything that uses IsROrC can probably just use reals), but that's fine to put off.
This argument is still needed for almost all the lemmas, which means it can longer be found by unification.
We keep around
expSeries 𝕂 A
, as it's needed for talking about the radius of convergence over different base fields.This is a prerequisite for #8372, as we can't merge the functions until they have the same interface.
This is started from the mathport output on leanprover-community/mathlib3#19244