Metamath Proof Explorer


Theorem dfcnvrefrels2

Description: Alternate definition of the class of converse reflexive relations. See the comment of dfrefrels2 . (Contributed by Peter Mazsa, 21-Jul-2021)

Ref Expression
Assertion dfcnvrefrels2 CnvRefRels = { 𝑟 ∈ Rels ∣ 𝑟 ⊆ ( I ∩ ( dom 𝑟 × ran 𝑟 ) ) }

Proof

Step Hyp Ref Expression
1 df-cnvrefrels CnvRefRels = ( CnvRefs ∩ Rels )
2 df-cnvrefs CnvRefs = { 𝑟 ∣ ( I ∩ ( dom 𝑟 × ran 𝑟 ) ) S ( 𝑟 ∩ ( dom 𝑟 × ran 𝑟 ) ) }
3 dmexg ( 𝑟 ∈ V → dom 𝑟 ∈ V )
4 3 elv dom 𝑟 ∈ V
5 rnexg ( 𝑟 ∈ V → ran 𝑟 ∈ V )
6 5 elv ran 𝑟 ∈ V
7 4 6 xpex ( dom 𝑟 × ran 𝑟 ) ∈ V
8 inex2g ( ( dom 𝑟 × ran 𝑟 ) ∈ V → ( I ∩ ( dom 𝑟 × ran 𝑟 ) ) ∈ V )
9 brcnvssr ( ( I ∩ ( dom 𝑟 × ran 𝑟 ) ) ∈ V → ( ( I ∩ ( dom 𝑟 × ran 𝑟 ) ) S ( 𝑟 ∩ ( dom 𝑟 × ran 𝑟 ) ) ↔ ( 𝑟 ∩ ( dom 𝑟 × ran 𝑟 ) ) ⊆ ( I ∩ ( dom 𝑟 × ran 𝑟 ) ) ) )
10 7 8 9 mp2b ( ( I ∩ ( dom 𝑟 × ran 𝑟 ) ) S ( 𝑟 ∩ ( dom 𝑟 × ran 𝑟 ) ) ↔ ( 𝑟 ∩ ( dom 𝑟 × ran 𝑟 ) ) ⊆ ( I ∩ ( dom 𝑟 × ran 𝑟 ) ) )
11 elrels6 ( 𝑟 ∈ V → ( 𝑟 ∈ Rels ↔ ( 𝑟 ∩ ( dom 𝑟 × ran 𝑟 ) ) = 𝑟 ) )
12 11 elv ( 𝑟 ∈ Rels ↔ ( 𝑟 ∩ ( dom 𝑟 × ran 𝑟 ) ) = 𝑟 )
13 12 biimpi ( 𝑟 ∈ Rels → ( 𝑟 ∩ ( dom 𝑟 × ran 𝑟 ) ) = 𝑟 )
14 13 sseq1d ( 𝑟 ∈ Rels → ( ( 𝑟 ∩ ( dom 𝑟 × ran 𝑟 ) ) ⊆ ( I ∩ ( dom 𝑟 × ran 𝑟 ) ) ↔ 𝑟 ⊆ ( I ∩ ( dom 𝑟 × ran 𝑟 ) ) ) )
15 10 14 syl5bb ( 𝑟 ∈ Rels → ( ( I ∩ ( dom 𝑟 × ran 𝑟 ) ) S ( 𝑟 ∩ ( dom 𝑟 × ran 𝑟 ) ) ↔ 𝑟 ⊆ ( I ∩ ( dom 𝑟 × ran 𝑟 ) ) ) )
16 1 2 15 abeqinbi CnvRefRels = { 𝑟 ∈ Rels ∣ 𝑟 ⊆ ( I ∩ ( dom 𝑟 × ran 𝑟 ) ) }