Theorem setrec1lem4 42437

Description: Lemma for setrec1 42438. If X is recursively generated by F, then so is X u. ( F ` A ).

In the proof of setrec1 42438, the following is substituted for this theorem's ph: ( ph /\ ( A C_ x /\ x e. { y | A. z ( A. w ( w C_ y -> ( w C_ z -> ( F ` w ) C_ z ) ) -> y C_ z ) } ) ) Therefore, we cannot declare z to be a distinct variable from ph, since we need it to appear as a bound variable in ph. This theorem can be proven without the hypothesis F/ z ph, but the proof would be harder to read because theorems in deduction form would be interrupted by theorems like eximi 1762, making the antecedent of each line something more complicated than ph. The proof of setrec1lem2 42435 could similarly be made easier to read by adding the hypothesis F/ z ph, but I had already finished the proof and decided to leave it as is. (Contributed by Emmett Weisz, 26-Nov-2020.) (New usage is discouraged.)

Hypotheses

Ref	Expression
setrec1lem4.1	|- F/ z ph
setrec1lem4.2	|- Y = { y | A. z ( A. w ( w C_ y -> ( w C_ z -> ( F ` w ) C_ z ) ) -> y C_ z ) }
setrec1lem4.3	|- ( ph -> A e. _V )
setrec1lem4.4	|- ( ph -> A C_ X )
setrec1lem4.5	|- ( ph -> X e. Y )

Assertion

Ref	Expression
setrec1lem4	|- ( ph -> ( X u. ( F ` A ) ) e. Y )

Distinct variable groups:   y, w, z, A   w, F, y, z   w, X, y, z

Allowed substitution hints:   ph( y, z, w)   Y( y, z, w)

Proof of Theorem setrec1lem4

Step	Hyp	Ref	Expression
1		setrec1lem4.1	. . 3 |- F/ z ph
2		id 22	. . . . . . . 8 |- ( w C_ X -> w C_ X )
3		ssun1 3776	. . . . . . . 8 |- X C_ ( X u. ( F ` A ) )
4	2, 3	syl6ss 3615	. . . . . . 7 |- ( w C_ X -> w C_ ( X u. ( F ` A ) ) )
5	4	imim1i 63	. . . . . 6 |- ( ( w C_ ( X u. ( F ` A ) ) -> ( w C_ z -> ( F ` w ) C_ z ) ) -> ( w C_ X -> ( w C_ z -> ( F ` w ) C_ z ) ) )
6	5	alimi 1739	. . . . 5 |- ( A. w ( w C_ ( X u. ( F ` A ) ) -> ( w C_ z -> ( F ` w ) C_ z ) ) -> A. w ( w C_ X -> ( w C_ z -> ( F ` w ) C_ z ) ) )
7		setrec1lem4.5	. . . . . . . 8 |- ( ph -> X e. Y )
8		setrec1lem4.2	. . . . . . . . 9 |- Y = { y | A. z ( A. w ( w C_ y -> ( w C_ z -> ( F ` w ) C_ z ) ) -> y C_ z ) }
9	8, 7	setrec1lem1 42434	. . . . . . . 8 |- ( ph -> ( X e. Y <-> A. z ( A. w ( w C_ X -> ( w C_ z -> ( F ` w ) C_ z ) ) -> X C_ z ) ) )
10	7, 9	mpbid 222	. . . . . . 7 |- ( ph -> A. z ( A. w ( w C_ X -> ( w C_ z -> ( F ` w ) C_ z ) ) -> X C_ z ) )
11		sp 2053	. . . . . . 7 |- ( A. z ( A. w ( w C_ X -> ( w C_ z -> ( F ` w ) C_ z ) ) -> X C_ z ) -> ( A. w ( w C_ X -> ( w C_ z -> ( F ` w ) C_ z ) ) -> X C_ z ) )
12	10, 11	syl 17	. . . . . 6 |- ( ph -> ( A. w ( w C_ X -> ( w C_ z -> ( F ` w ) C_ z ) ) -> X C_ z ) )
13		setrec1lem4.4	. . . . . . . . 9 |- ( ph -> A C_ X )
14		sstr2 3610	. . . . . . . . 9 |- ( A C_ X -> ( X C_ z -> A C_ z ) )
15	13, 14	syl 17	. . . . . . . 8 |- ( ph -> ( X C_ z -> A C_ z ) )
16	12, 15	syld 47	. . . . . . 7 |- ( ph -> ( A. w ( w C_ X -> ( w C_ z -> ( F ` w ) C_ z ) ) -> A C_ z ) )
17		setrec1lem4.3	. . . . . . . . 9 |- ( ph -> A e. _V )
18		sseq1 3626	. . . . . . . . . 10 |- ( w = A -> ( w C_ X <-> A C_ X ) )
19		sseq1 3626	. . . . . . . . . . 11 |- ( w = A -> ( w C_ z <-> A C_ z ) )
20		fveq2 6191	. . . . . . . . . . . 12 |- ( w = A -> ( F ` w ) = ( F ` A ) )
21	20	sseq1d 3632	. . . . . . . . . . 11 |- ( w = A -> ( ( F ` w ) C_ z <-> ( F ` A ) C_ z ) )
22	19, 21	imbi12d 334	. . . . . . . . . 10 |- ( w = A -> ( ( w C_ z -> ( F ` w ) C_ z ) <-> ( A C_ z -> ( F ` A ) C_ z ) ) )
23	18, 22	imbi12d 334	. . . . . . . . 9 |- ( w = A -> ( ( w C_ X -> ( w C_ z -> ( F ` w ) C_ z ) ) <-> ( A C_ X -> ( A C_ z -> ( F ` A ) C_ z ) ) ) )
24	17, 23	spcdvw 42426	. . . . . . . 8 |- ( ph -> ( A. w ( w C_ X -> ( w C_ z -> ( F ` w ) C_ z ) ) -> ( A C_ X -> ( A C_ z -> ( F ` A ) C_ z ) ) ) )
25	13, 24	mpid 44	. . . . . . 7 |- ( ph -> ( A. w ( w C_ X -> ( w C_ z -> ( F ` w ) C_ z ) ) -> ( A C_ z -> ( F ` A ) C_ z ) ) )
26	16, 25	mpdd 43	. . . . . 6 |- ( ph -> ( A. w ( w C_ X -> ( w C_ z -> ( F ` w ) C_ z ) ) -> ( F ` A ) C_ z ) )
27	12, 26	jcad 555	. . . . 5 |- ( ph -> ( A. w ( w C_ X -> ( w C_ z -> ( F ` w ) C_ z ) ) -> ( X C_ z /\ ( F ` A ) C_ z ) ) )
28	6, 27	syl5 34	. . . 4 |- ( ph -> ( A. w ( w C_ ( X u. ( F ` A ) ) -> ( w C_ z -> ( F ` w ) C_ z ) ) -> ( X C_ z /\ ( F ` A ) C_ z ) ) )
29		unss 3787	. . . 4 |- ( ( X C_ z /\ ( F ` A ) C_ z ) <-> ( X u. ( F ` A ) ) C_ z )
30	28, 29	syl6ib 241	. . 3 |- ( ph -> ( A. w ( w C_ ( X u. ( F ` A ) ) -> ( w C_ z -> ( F ` w ) C_ z ) ) -> ( X u. ( F ` A ) ) C_ z ) )
31	1, 30	alrimi 2082	. 2 |- ( ph -> A. z ( A. w ( w C_ ( X u. ( F ` A ) ) -> ( w C_ z -> ( F ` w ) C_ z ) ) -> ( X u. ( F ` A ) ) C_ z ) )
32		fvex 6201	. . . 4 |- ( F ` A ) e. _V
33		unexg 6959	. . . 4 |- ( ( X e. Y /\ ( F ` A ) e. _V ) -> ( X u. ( F ` A ) ) e. _V )
34	7, 32, 33	sylancl 694	. . 3 |- ( ph -> ( X u. ( F ` A ) ) e. _V )
35	8, 34	setrec1lem1 42434	. 2 |- ( ph -> ( ( X u. ( F ` A ) ) e. Y <-> A. z ( A. w ( w C_ ( X u. ( F ` A ) ) -> ( w C_ z -> ( F ` w ) C_ z ) ) -> ( X u. ( F ` A ) ) C_ z ) ) )
36	31, 35	mpbird 247	1 |- ( ph -> ( X u. ( F ` A ) ) e. Y )

Syntax hints:   -> wi 4   /\ wa 384   A.wal 1481   = wceq 1483   F/wnf 1708   e. wcel 1990   {cab 2608   _Vcvv 3200   u. cun 3572   C_ wss 3574   ` cfv 5888

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-8 1992  ax-9 1999  ax-10 2019  ax-11 2034  ax-12 2047  ax-13 2246  ax-ext 2602  ax-sep 4781  ax-nul 4789  ax-pr 4906  ax-un 6949

This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3an 1039  df-tru 1486  df-ex 1705  df-nf 1710  df-sb 1881  df-eu 2474  df-clab 2609  df-cleq 2615  df-clel 2618  df-nfc 2753  df-ral 2917  df-rex 2918  df-rab 2921  df-v 3202  df-sbc 3436  df-dif 3577  df-un 3579  df-in 3581  df-ss 3588  df-nul 3916  df-if 4087  df-sn 4178  df-pr 4180  df-op 4184  df-uni 4437  df-br 4654  df-iota 5851  df-fv 5896

This theorem is referenced by:  setrec1  42438