Definition df-eldisj 39331

Description: Define the disjoint element relation predicate, i.e., the disjoint elementhood predicate. Read: the elements of 𝐴 are disjoint. The element of the disjoint elements class and the disjoint elementhood predicate are the same, that is (𝐴 ∈ ElDisjs ↔ ElDisj 𝐴) when 𝐴 is a set, see eleldisjseldisj 39368.

As of now, disjoint elementhood is defined as "partition" in set.mm : compare df-prt 39536 with dfeldisj5 39352. See also the comments of dfmembpart2 39412 and of df-parts 39407. (Contributed by Peter Mazsa, 17-Jul-2021.)

Assertion

Ref	Expression
df-eldisj	⊢ ( ElDisj 𝐴 ↔ Disj (◡ E ↾ 𝐴))

Detailed syntax breakdown of Definition df-eldisj

Step	Hyp	Ref	Expression
1		cA	. . 3 class 𝐴
2	1	weldisj 38760	. 2 wff ElDisj 𝐴
3		cep 5561	. . . . 5 class E
4	3	ccnv 5661	. . . 4 class ◡ E
5	4, 1	cres 5664	. . 3 class (◡ E ↾ 𝐴)
6	5	wdisjALTV 38758	. 2 wff Disj (◡ E ↾ 𝐴)
7	2, 6	wb 209	1 wff ( ElDisj 𝐴 ↔ Disj (◡ E ↾ 𝐴))

This definition is referenced by:  dfeldisj2  39349  dfeldisj3  39350  dfeldisj4  39351  eleldisjseldisj  39368  eldisjss  39377  eldisjeq  39380  eldisjn0elb  39384  dfmembpart2  39412  eldisjim  39426  eldisjim2  39427  eldisjn0el  39448  eldisjlem19  39452  eqvreldisj3  39468