mathlib

520f2046 - feat(analysis/seminorm): add lemmas for inequalities and `finset.sup` (#12650)

feat(analysis/seminorm): add lemmas for inequalities and `finset.sup` (#12650) These lemmas are not lean-trivial since seminorms map to the `real` and not to `nnreal`. Co-authored-by: Eric Wieser <wieser.eric@gmail.com>