Commit 2021-11-08 16:03 1519cd77
View on Github →chore(set_theory/cardinal): more simp, fix LHS/RHS (#10212)
While coe (fintype.card α)
is a larger expression than #α
, it allows us to compute the cardinality of a finite type provided that we have a simp
lemma for fintype.card α
. It also plays well with lemmas about coercions from nat
and cardinal.lift
.
- rename
cardinal.fintype_card
tocardinal.mk_fintype
, make it a@[simp]
lemma; - deduce other cases (
bool
,Prop
,unique
,is_empty
) from it; - rename
cardinal.finset_card
tocardinal.mk_finset
, swap LHS/RHS; - rename
ordinal.fintype_card
toordinal.type_fintype
.