Zulip Chat Archive

Stream: Is there code for X?

Topic: hasDerivWithinAt_pi for EuclideanSpace or Lp normed spaces


Michael Novak (Feb 22 2026 at 11:24):

Is there a theorem like docs#hasDerivWithinAt_pi for EuclideanSpace or normed Lp spaces? I can't find something exactly like this. Alternatively is there some other way of getting this?

Yury G. Kudryashov (Feb 22 2026 at 14:01):

You can add a pi version of docs#WithLp.prodContinuousLinearEquiv (probably, generalizing docs#EuclideanSpace.equiv), then combine the existing theorem with theorems about differentiabilty of ContinuousLinearEquivs.

Michael Novak (Feb 22 2026 at 16:46):

Yury G. Kudryashov said:

You can add a pi version of docs#WithLp.prodContinuousLinearEquiv (probably, generalizing docs#EuclideanSpace.equiv), then combine the existing theorem with theorems about differentiabilty of ContinuousLinearEquivs.

Thank you very much!

Albert Smith (Feb 22 2026 at 16:54):

The equiv Yury suggests already exists, I believe, as docs#PiLp.continuousLinearEquiv

Yury G. Kudryashov (Feb 22 2026 at 17:33):

I forgot that loogle doesn't see through abbrevs.

Yury G. Kudryashov (Feb 22 2026 at 21:21):

:man_facepalming: See docs#differentiableWithinAt_piLp and other lemmas in that file.

Albert Smith (Feb 22 2026 at 21:36):

It seems there's also docs#hasFDerivWithinAt_euclidean for the special case of Euclidean space


Last updated: Feb 28 2026 at 14:05 UTC