Definition df-mbf 20941

Description: Define the class of measurable functions on the reals. A real function is measurable if the preimage of every open interval is a measurable set (see ismbl 20851) and a complex function is measurable if the real and imaginary parts of the function is measurable. (Contributed by Mario Carneiro, 17-Jun-2014.)

Assertion

Ref	Expression
df-mbf	|- MblFn = { f e. ( CC ^pm RR ) | A. x e. ran (,) ( ( `' ( Re o. f ) " x ) e. dom vol /\ ( `' ( Im o. f ) " x ) e. dom vol ) }

Distinct variable group:   x, f

Detailed syntax breakdown of Definition df-mbf

Step	Hyp	Ref	Expression
1		cmbf 20936	. 2 class MblFn
2		cre 12570	. . . . . . . . 9 class Re
3		vf	. . . . . . . . . 10 setvar f
4	3	cv 1361	. . . . . . . . 9 class f
5	2, 4	ccom 4831	. . . . . . . 8 class ( Re o. f )
6	5	ccnv 4826	. . . . . . 7 class `' ( Re o. f )
7		vx	. . . . . . . 8 setvar x
8	7	cv 1361	. . . . . . 7 class x
9	6, 8	cima 4830	. . . . . 6 class ( `' ( Re o. f ) " x )
10		cvol 20789	. . . . . . 7 class vol
11	10	cdm 4827	. . . . . 6 class dom vol
12	9, 11	wcel 1755	. . . . 5 wff ( `' ( Re o. f ) " x ) e. dom vol
13		cim 12571	. . . . . . . . 9 class Im
14	13, 4	ccom 4831	. . . . . . . 8 class ( Im o. f )
15	14	ccnv 4826	. . . . . . 7 class `' ( Im o. f )
16	15, 8	cima 4830	. . . . . 6 class ( `' ( Im o. f ) " x )
17	16, 11	wcel 1755	. . . . 5 wff ( `' ( Im o. f ) " x ) e. dom vol
18	12, 17	wa 369	. . . 4 wff ( ( `' ( Re o. f ) " x ) e. dom vol /\ ( `' ( Im o. f ) " x ) e. dom vol )
19		cioo 11288	. . . . 5 class (,)
20	19	crn 4828	. . . 4 class ran (,)
21	18, 7, 20	wral 2705	. . 3 wff A. x e. ran (,) ( ( `' ( Re o. f ) " x ) e. dom vol /\ ( `' ( Im o. f ) " x ) e. dom vol )
22		cc 9268	. . . 4 class CC
23		cr 9269	. . . 4 class RR
24		cpm 7203	. . . 4 class ^pm
25	22, 23, 24	co 6080	. . 3 class ( CC ^pm RR )
26	21, 3, 25	crab 2709	. 2 class { f e. ( CC ^pm RR ) | A. x e. ran (,) ( ( `' ( Re o. f ) " x ) e. dom vol /\ ( `' ( Im o. f ) " x ) e. dom vol ) }
27	1, 26	wceq 1362	1 wff MblFn = { f e. ( CC ^pm RR ) | A. x e. ran (,) ( ( `' ( Re o. f ) " x ) e. dom vol /\ ( `' ( Im o. f ) " x ) e. dom vol ) }

This definition is referenced by:  ismbf1  20946