Definition df-disjs 38660

Description: Define the disjoint relations class, i.e., the class of disjoints. We need Disjs for the definition of Parts and Part for the Partition-Equivalence Theorems: this need for Parts as disjoint relations on their domain quotients is the reason why we must define Disjs instead of simply using converse functions (cf. dfdisjALTV 38669).

The element of the class of disjoints and the disjoint predicate are the same, that is (𝑅 ∈ Disjs ↔ Disj 𝑅) when 𝑅 is a set, see eldisjsdisj 38683. Alternate definitions are dfdisjs 38664, ... , dfdisjs5 38668. (Contributed by Peter Mazsa, 17-Jul-2021.)

Assertion

Ref	Expression
df-disjs	⊢ Disjs = ( Disjss ∩ Rels )

Detailed syntax breakdown of Definition df-disjs

Step	Hyp	Ref	Expression
1		cdisjs 38168	. 2 class Disjs
2		cdisjss 38167	. . 3 class Disjss
3		crels 38137	. . 3 class Rels
4	2, 3	cin 3975	. 2 class ( Disjss ∩ Rels )
5	1, 4	wceq 1537	1 wff Disjs = ( Disjss ∩ Rels )

This definition is referenced by:  dfdisjs  38664