Description: Lemma for frege72 . Proposition 70 of Frege1879 p. 58. (Contributed by RP, 28-Mar-2020) (Revised by RP, 3-Jul-2020) (Proof modification is discouraged.)
Ref | Expression | ||
---|---|---|---|
Hypothesis | frege70.x | |
|
Assertion | frege70 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | frege70.x | |
|
2 | dffrege69 | |
|
3 | 1 | frege68c | |
4 | sbcel1v | |
|
5 | 4 | biimpri | |
6 | sbcim1 | |
|
7 | sbcal | |
|
8 | sbcim1 | |
|
9 | sbcbr1g | |
|
10 | 1 9 | ax-mp | |
11 | csbvarg | |
|
12 | 1 11 | ax-mp | |
13 | 12 | breq1i | |
14 | 10 13 | bitri | |
15 | sbcg | |
|
16 | 1 15 | ax-mp | |
17 | 8 14 16 | 3imtr3g | |
18 | 17 | alimi | |
19 | 7 18 | sylbi | |
20 | 5 6 19 | syl56 | |
21 | 3 20 | syl6 | |
22 | 2 21 | ax-mp | |