Description: The alternate function value at a class A is undefined if the function, whose range is a set, is not defined at A . (Contributed by AV, 2-Sep-2022)
Ref | Expression | ||
---|---|---|---|
Assertion | ndfatafv2undef |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ndfatafv2 | ||
2 | undefval | ||
3 | 2 | eqcomd | |
4 | 1 3 | sylan9eqr |