Description: The union of the Lebesgue measurable sets is RR . (Contributed by Thierry Arnoux, 30-Jan-2017)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | unidmvol | |- U. dom vol = RR  | 
				
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | unissb | |- ( U. dom vol C_ RR <-> A. x e. dom vol x C_ RR )  | 
						|
| 2 | mblss | |- ( x e. dom vol -> x C_ RR )  | 
						|
| 3 | 1 2 | mprgbir | |- U. dom vol C_ RR  | 
						
| 4 | rembl | |- RR e. dom vol  | 
						|
| 5 | unissel | |- ( ( U. dom vol C_ RR /\ RR e. dom vol ) -> U. dom vol = RR )  | 
						|
| 6 | 3 4 5 | mp2an | |- U. dom vol = RR  |