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Reorganize proofs of implications from cancellativity
1 parent 19acec9 commit c170f55

2 files changed

Lines changed: 2 additions & 16 deletions

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databases/catdat/data/005_implications/001_limits-colimits-existence-implications.sql

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@@ -76,20 +76,6 @@ VALUES
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'In a thin category, any congruence pair is a reflexive fork, and thus consists of equal isomorphisms. Therefore, the congruence is the kernel pair of the identity morphism on the target.',
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FALSE
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),
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(
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'left_cancellative_effective_congruences',
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'["left cancellative"]',
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'["effective congruences"]',
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'For any congruence $f, g : E \rightrightarrows X$, if $r$ is the reflexivity morphism we have $r$ is both an epimorphism and a split monomorphism, so it is an isomorphism. Therefore, $f\circ r = g\circ r = \mathrm{id}_X$ implies $f = g$. As <a href="core-hin_quotients">here</a>, that implies that $E$ is the kernel pair of $\mathrm{id}_X$.',
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FALSE
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),
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(
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'right_cancellative_effective_congruences',
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'["right cancellative"]',
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'["effective congruences"]',
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'For any congruence $f, g : E \rightrightarrows X$, if $r$ is the reflexivity morphism we have $f\circ r = g\circ r = \mathrm{id}_X$, so $f = g$. As <a href="core-hin_quotients">here</a>, that implies that $E$ is the kernel pair of $\mathrm{id}_X$.',
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FALSE
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),
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(
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'products_consequences',
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'["products"]',

databases/catdat/data/005_implications/004_morphism-behavior-implications.sql

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@@ -37,8 +37,8 @@ VALUES
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(
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'reflexive_pair_trivial',
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'["left cancellative"]',
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'["reflexive coequalizers", "coreflexive equalizers"]',
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'Any parallel pair of morphisms with a common section (or retraction) must be a pair of equal isomorphisms.',
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'["reflexive coequalizers", "coreflexive equalizers", "effective congruences", "effective cocongruences"]',
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'Any parallel pair of morphisms with a common section (or retraction) must be a pair of equal isomorphisms. In particular, they are the kernel pair of the identity morphism on the target, and the cokernel pair of the identity morphism on the source.',
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FALSE
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),
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(

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