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Mathlib.Algebra.Category.Ring.Colimits

The category of commutative rings has all colimits. #

This file uses a "pre-automated" approach, just as for Mathlib/Algebra/Category/MonCat/Colimits.lean. It is a very uniform approach, that conceivably could be synthesised directly by a tactic that analyses the shape of CommRing and RingHom.

We build the colimit of a diagram in RingCat by constructing the free ring on the disjoint union of all the rings in the diagram, then taking the quotient by the ring laws within each ring, and the identifications given by the morphisms in the diagram.

An inductive type representing all ring expressions (without Relations) on a collection of types indexed by the objects of J.

The Relation on Prequotient saying when two expressions are equal because of the ring laws, or because one element is mapped to another by a morphism in the diagram.

The setoid corresponding to commutative expressions modulo monoid Relations and identifications.

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The function from a given ring in the diagram to the colimit ring.

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The ring homomorphism from a given ring in the diagram to the colimit ring.

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@[simp]

The function from the free ring on the diagram to the cone point of any other cocone.

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The function from the colimit ring to the cone point of any other cocone.

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The ring homomorphism from the colimit ring to the cone point of any other cocone.

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We build the colimit of a diagram in CommRingCat by constructing the free commutative ring on the disjoint union of all the commutative rings in the diagram, then taking the quotient by the commutative ring laws within each commutative ring, and the identifications given by the morphisms in the diagram.

The Relation on Prequotient saying when two expressions are equal because of the commutative ring laws, or because one element is mapped to another by a morphism in the diagram.

The setoid corresponding to commutative expressions modulo monoid Relations and identifications.

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The function from a given commutative ring in the diagram to the colimit commutative ring.

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The ring homomorphism from a given commutative ring in the diagram to the colimit commutative ring.

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The function from the colimit commutative ring to the cone point of any other cocone.

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The ring homomorphism from the colimit commutative ring to the cone point of any other cocone.

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