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SUPPLEMENTARY MATERIAL (USERS' MATHBOXES)
Mathbox for Peter Mazsa
Partition-Equivalence Theorems
petxrnidres
Metamath Proof Explorer
Description: A class is a partition by a range Cartesian product with the identity
class restricted to it if and only if the cosets by the range Cartesian
product are in equivalence relation on it. Cf. br1cossxrnidres ,
disjALTVxrnidres and eqvrel1cossxrnidres . (Contributed by Peter
Mazsa , 31-Dec-2021)
Ref
Expression
Assertion
petxrnidres
⊢ R ⋉ I ↾ A Part A ↔ ≀ R ⋉ I ↾ A ErALTV A
Proof
Step
Hyp
Ref
Expression
1
petxrnidres2
⊢ Disj R ⋉ I ↾ A ∧ dom ⁡ R ⋉ I ↾ A / R ⋉ I ↾ A = A ↔ EqvRel ≀ R ⋉ I ↾ A ∧ dom ⁡ ≀ R ⋉ I ↾ A / ≀ R ⋉ I ↾ A = A
2
dfpart2
⊢ R ⋉ I ↾ A Part A ↔ Disj R ⋉ I ↾ A ∧ dom ⁡ R ⋉ I ↾ A / R ⋉ I ↾ A = A
3
dferALTV2
⊢ ≀ R ⋉ I ↾ A ErALTV A ↔ EqvRel ≀ R ⋉ I ↾ A ∧ dom ⁡ ≀ R ⋉ I ↾ A / ≀ R ⋉ I ↾ A = A
4
1 2 3
3bitr4i
⊢ R ⋉ I ↾ A Part A ↔ ≀ R ⋉ I ↾ A ErALTV A