mathlib3

4f31117e - feat(data/set/basic): add `set.subset_range_iff_exists_image_eq` and `set.range_image` (#14203)

feat(data/set/basic): add `set.subset_range_iff_exists_image_eq` and `set.range_image` (#14203) * add `set.subset_range_iff_exists_image_eq` and `set.range_image`; * use the former to golf `set.can_lift` (name fixed from `set.set.can_lift`); * golf `set.exists_eq_singleton_iff_nonempty_subsingleton`.