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algebra.category.Ring.adjunctions

Multivariable polynomials on a type is the left adjoint of the forgetful functor from commutative rings to types.

noncomputable def CommRing.free  :

The free functor Type u ⥤ CommRing sending a type X to the multivariable (commutative) polynomials with variables x : X.

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theorem CommRing.free_map_coe {α β : Type u} {f : α β} :

The free-forgetful adjunction for commutative rings.

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