Metamath Proof Explorer


Theorem measvxrge0

Description: The values of a measure are positive extended reals. (Contributed by Thierry Arnoux, 26-Dec-2016)

Ref Expression
Assertion measvxrge0
|- ( ( M e. ( measures ` S ) /\ A e. S ) -> ( M ` A ) e. ( 0 [,] +oo ) )

Proof

Step Hyp Ref Expression
1 measfrge0
 |-  ( M e. ( measures ` S ) -> M : S --> ( 0 [,] +oo ) )
2 1 ffvelrnda
 |-  ( ( M e. ( measures ` S ) /\ A e. S ) -> ( M ` A ) e. ( 0 [,] +oo ) )