Definition df-dm 4821

Description: Define the domain of a class. Definition 3 of [Suppes] p. 59. For example, ={<.2,6>.,<.3,9>.}->dom={2,3} (ex-dm 23325). Another example is the domain of the complex arctangent, (for proof see atandm 22012). Contrast with range (defined in df-rn 4822). For alternate definitions see dfdm2 5341, dfdm3 4998, and dfdm4 5003. The notation "dom " is used by Enderton; other authors sometimes use script D. (Contributed by NM, 1-Aug-1994.)

Assertion

Ref	Expression
df-dm

Distinct variable group:   ,,

Detailed syntax breakdown of Definition df-dm

Step	Hyp	Ref	Expression
1		cA	. . 3
2	1	cdm 4811	. 2
3		vx	. . . . . 6
4	3	cv 1686	. . . . 5
5		vy	. . . . . 6
6	5	cv 1686	. . . . 5
7	4, 6, 1	wbr 4267	. . . 4
8	7, 5	wex 1581	. . 3
9	8, 3	cab 2408	. 2
10	2, 9	wceq 1687	1

This definition is referenced by:  dfdm3  4998  dfrn2  4999  dfdm4  5003  dfdmf  5004  eldmg  5006  dmun  5017  dm0rn0  5027  nfdm  5052  fliftf  5976  opabdm  25623  domep  27308