Description: Inference that has ax-12 (without A. y ) as its conclusion. Uses only Tarski's FOL axiom schemes. The hypotheses may be eliminable without using ax-12 in special cases. Proof similar to Lemma 16 of Tarski p. 70. (Contributed by NM, 20-May-2008)
Ref | Expression | ||
---|---|---|---|
Hypotheses | ax12i.1 | |
|
ax12i.2 | |
||
Assertion | ax12i | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ax12i.1 | |
|
2 | ax12i.2 | |
|
3 | 1 | biimprcd | |
4 | 2 3 | alrimih | |
5 | 1 4 | syl6bi | |