Description: Value of the delta measure. (Contributed by Thierry Arnoux, 14-Sep-2018)
Ref | Expression | ||
---|---|---|---|
Assertion | ddeval0 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | reex | |
|
2 | 1 | ssex | |
3 | elpwg | |
|
4 | 3 | biimpar | |
5 | 2 4 | mpancom | |
6 | eleq2 | |
|
7 | 6 | ifbid | |
8 | df-dde | |
|
9 | 1ex | |
|
10 | c0ex | |
|
11 | 9 10 | ifex | |
12 | 7 8 11 | fvmpt | |
13 | 5 12 | syl | |
14 | iffalse | |
|
15 | 13 14 | sylan9eq | |