Definition df-dm 4967

Description: Define the domain of a class. Definition 3 of [Suppes] p. 59. For example, ={<.2,6>.,<.3,9>.}->dom={2,3} (ex-dm 24115). Another example is the domain of the complex arctangent, (for proof see atandm 22671). Contrast with range (defined in df-rn 4968). For alternate definitions see dfdm2 5488, dfdm3 5144, and dfdm4 5149. 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 4957	. 2
3		vx	. . . . . 6
4	3	cv 1369	. . . . 5
5		vy	. . . . . 6
6	5	cv 1369	. . . . 5
7	4, 6, 1	wbr 4409	. . . 4
8	7, 5	wex 1587	. . 3
9	8, 3	cab 2439	. 2
10	2, 9	wceq 1370	1

This definition is referenced by:  dfdm3  5144  dfrn2  5145  dfdm4  5149  dfdmf  5150  eldmg  5152  dmun  5163  dm0rn0  5173  nfdm  5198  fliftf  6139  opabdm  26411  domep  28062