[Merged by Bors] - feat(RingTheory/FiniteType): generalize some results to non-commutative rings #6681
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I was hoping to use this in combination with #6680 to show the
TensorAlgebra
is finitely generated, where I needed to generalizeFiniteType.equiv
; but it turns out that theFiniteType
instance onMonoidAlgebra
also isn't generalized!The summary here is:
Algebra.adjoin_algebraMap
fromMathlib/RingTheory/Adjoin/Tower.lean
toMathlib/RingTheory/Adjoin/Basic.lean
and golf the proof to oblivionadjoin_union_eq_adjoin_adjoin
,adjoin_algebraMap_image_union_eq_adjoin_adjoin
, which works in non-commutative rings, and use it along with a newadjoin_top
lemma to proveAlgebra.fg_trans'
more generally.S
variable throughout, with the convention thatR
andS
are commutative,A
andB
remain not-necessarily-commutative, andA/S/R
is a tower of algebras.