Metamath Proof Explorer


Definition df-ae

Description: Define 'almost everywhere' with regard to a measure M . A property holds almost everywhere if the measure of the set where it does not hold has measure zero. (Contributed by Thierry Arnoux, 20-Oct-2017)

Ref Expression
Assertion df-ae ⊢ ae = a m | m ⁡ ⋃ dom ⁡ m ∖ a = 0

Detailed syntax breakdown

Step Hyp Ref Expression
0 cae class ae
1 va setvar a
2 vm setvar m
3 2 cv setvar m
4 3 cdm class dom ⁡ m
5 4 cuni class ⋃ dom ⁡ m
6 1 cv setvar a
7 5 6 cdif class ⋃ dom ⁡ m ∖ a
8 7 3 cfv class m ⁡ ⋃ dom ⁡ m ∖ a
9 cc0 class 0
10 8 9 wceq wff m ⁡ ⋃ dom ⁡ m ∖ a = 0
11 10 1 2 copab class a m | m ⁡ ⋃ dom ⁡ m ∖ a = 0
12 0 11 wceq wff ae = a m | m ⁡ ⋃ dom ⁡ m ∖ a = 0