Description: If the procedure R is single-valued and if M and Y follow X in the R -sequence, then Y belongs to the R -sequence beginning with M or precedes M in the R -sequence. Proposition 133 of Frege1879 p. 86. (Contributed by RP, 9-Jul-2020) (Proof modification is discouraged.)
Ref | Expression | ||
---|---|---|---|
Hypotheses | frege133.x | |
|
frege133.y | |
||
frege133.m | |
||
frege133.r | |
||
Assertion | frege133 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | frege133.x | |
|
2 | frege133.y | |
|
3 | frege133.m | |
|
4 | frege133.r | |
|
5 | fvex | |
|
6 | 5 | cnvex | |
7 | imaexg | |
|
8 | 6 7 | ax-mp | |
9 | imaundir | |
|
10 | imaexg | |
|
11 | 5 10 | ax-mp | |
12 | imai | |
|
13 | snex | |
|
14 | 12 13 | eqeltri | |
15 | 11 14 | unex | |
16 | 9 15 | eqeltri | |
17 | 1 2 4 8 16 | frege83 | |
18 | 3 | elexi | |
19 | 1 | elexi | |
20 | 18 19 | elimasn | |
21 | df-br | |
|
22 | 18 19 | brcnv | |
23 | 20 21 22 | 3bitr2i | |
24 | elun | |
|
25 | df-or | |
|
26 | 2 | elexi | |
27 | 18 26 | elimasn | |
28 | df-br | |
|
29 | 18 26 | brcnv | |
30 | 27 28 29 | 3bitr2i | |
31 | 30 | notbii | |
32 | 18 26 | elimasn | |
33 | df-br | |
|
34 | 32 33 | bitr4i | |
35 | 31 34 | imbi12i | |
36 | 24 25 35 | 3bitri | |
37 | 36 | imbi2i | |
38 | 23 37 | imbi12i | |
39 | 38 | imbi2i | |
40 | 3 4 | frege132 | |
41 | 39 40 | sylbi | |
42 | 17 41 | ax-mp | |