Why Nostr? What is Njump?
2025-04-15 03:29:04
in reply to

Tom_Drummond on Nostr: nprofile1q…r59k6 Another way I have used to get at the exponential map when I'm ...

Another way I have used to get at the exponential map when I'm teaching is the series \( \exp(x) = \lim_{n\to\infty} \left( I+\tfrac{x}{n} \right)^n\). We're still working embedded in GL(n), but the intuition is that if \( x \) is in the tangent space at \( I \) then \( I+\tfrac{x}{n} \) converges onto the group manifold as \( n\to\infty \). Then raising this group element to some power gives us a group element back by closure.

I admit this is still much less elegant than defining in terms of a derivation but it seems less like cheating to me... whereas the Taylor series approach does feel like pulling a rabbit from a hat.
Author Public Key
npub1g4ss3v8573z4aus0ytsq3ewah9cphk5p48ffnfz5hp8htsc9ndjqphtq97