Description: Lemma for transfinite recursion. A is the class of all "acceptable" functions, and F is their union. First we show that an acceptable function is in fact a function. (Contributed by NM, 9-Apr-1995)
Ref | Expression | ||
---|---|---|---|
Hypothesis | tfrlem.1 | |
|
Assertion | tfrlem4 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | tfrlem.1 | |
|
2 | 1 | tfrlem3 | |
3 | 2 | eqabri | |
4 | fnfun | |
|
5 | 4 | adantr | |
6 | 5 | rexlimivw | |
7 | 3 6 | sylbi | |