Description: If a function value has a member, then the function is not an empty set (An artifact of our function value definition.) (Contributed by Zhi Wang, 16-Sep-2024)
Ref | Expression | ||
---|---|---|---|
Assertion | elfvne0 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ne0i | ||
2 | fveq1 | ||
3 | 0fv | ||
4 | 2 3 | eqtrdi | |
5 | 4 | necon3i | |
6 | 1 5 | syl |