Definition df-dm 2428

Description: Define the domain of a class. Definition 3 of [Suppes] p. 59.

Assertion

Ref	Expression
df-dm	⊢ dom A = {x∣∃y xAy}

Distinct variable group(s):   x,y,A

Detailed syntax breakdown of Definition df-dm

Step	Hyp	Ref	Expression
1		cA	. . 3 class A
2	1	cdm 2410	. 2 class dom A
3		vx	. . . . . 6 set x
4	3	cv 1089	. . . . 5 class x
5		vy	. . . . . 6 set y
6	5	cv 1089	. . . . 5 class y
7	4, 6, 1	wbr 2054	. . . 4 wff xAy
8	7, 5	wex 678	. . 3 wff ∃y xAy
9	8, 3	cab 1090	. 2 class {x∣∃y xAy}
10	2, 9	wceq 1091	1 wff dom A = {x∣∃y xAy}

This definition is referenced by:  dfdm3 2522  dfrn2 2523  dfdm4 2525  eldm 2527  dmi 2545  dm0rn0 2549  dmco 2570  dmco2 2673

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