Description: Part of proof of Lemma E in Crawley p. 113. (Contributed by NM, 31-Mar-2013) (New usage is discouraged.)
Ref | Expression | ||
---|---|---|---|
Hypotheses | cdleme31sdn.c | ||
cdleme31sdn.d | |||
cdleme31sdn.n | |||
Assertion | cdleme31sdnN |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | cdleme31sdn.c | ||
2 | cdleme31sdn.d | ||
3 | cdleme31sdn.n | ||
4 | biid | ||
5 | 2 1 | cdleme31sc | |
6 | 5 | elv | |
7 | 4 6 | ifbieq2i | |
8 | 3 7 | eqtr4i |