Definition df-dm 5014

Description: Define the domain of a class. Definition 3 of [Suppes] p. 59. For example, ={<.2,6>.,<.3,9>.}->dom={2,3} (ex-dm 25160). Another example is the domain of the complex arctangent, (for proof see atandm 23207). Contrast with range (defined in df-rn 5015). For alternate definitions see dfdm2 5544, dfdm3 5195, and dfdm4 5200. 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 5004	. 2
3		vx	. . . . . 6
4	3	cv 1394	. . . . 5
5		vy	. . . . . 6
6	5	cv 1394	. . . . 5
7	4, 6, 1	wbr 4452	. . . 4
8	7, 5	wex 1612	. . 3
9	8, 3	cab 2442	. 2
10	2, 9	wceq 1395	1

This definition is referenced by:  dfdm3  5195  dfrn2  5196  dfdm4  5200  dfdmf  5201  eldmg  5203  dmun  5214  dm0rn0  5224  nfdm  5249  fliftf  6213  opabdm  27464  domep  29225