Metamath Proof Explorer


Theorem jm2.16nn0

Description: Lemma 2.16 of JonesMatijasevic p. 695. This may be regarded as a special case of jm2.15nn0 if rmY is redefined as described in rmyluc . (Contributed by Stefan O'Rear, 1-Oct-2014)

Ref Expression
Assertion jm2.16nn0
|- ( ( A e. ( ZZ>= ` 2 ) /\ N e. NN0 ) -> ( A - 1 ) || ( ( A rmY N ) - N ) )

Proof

Step Hyp Ref Expression
1 eluzelz
 |-  ( A e. ( ZZ>= ` 2 ) -> A e. ZZ )
2 peano2zm
 |-  ( A e. ZZ -> ( A - 1 ) e. ZZ )
3 1 2 syl
 |-  ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) e. ZZ )
4 0z
 |-  0 e. ZZ
5 congid
 |-  ( ( ( A - 1 ) e. ZZ /\ 0 e. ZZ ) -> ( A - 1 ) || ( 0 - 0 ) )
6 3 4 5 sylancl
 |-  ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( 0 - 0 ) )
7 rmy0
 |-  ( A e. ( ZZ>= ` 2 ) -> ( A rmY 0 ) = 0 )
8 7 oveq1d
 |-  ( A e. ( ZZ>= ` 2 ) -> ( ( A rmY 0 ) - 0 ) = ( 0 - 0 ) )
9 6 8 breqtrrd
 |-  ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( ( A rmY 0 ) - 0 ) )
10 1z
 |-  1 e. ZZ
11 congid
 |-  ( ( ( A - 1 ) e. ZZ /\ 1 e. ZZ ) -> ( A - 1 ) || ( 1 - 1 ) )
12 3 10 11 sylancl
 |-  ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( 1 - 1 ) )
13 rmy1
 |-  ( A e. ( ZZ>= ` 2 ) -> ( A rmY 1 ) = 1 )
14 13 oveq1d
 |-  ( A e. ( ZZ>= ` 2 ) -> ( ( A rmY 1 ) - 1 ) = ( 1 - 1 ) )
15 12 14 breqtrrd
 |-  ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( ( A rmY 1 ) - 1 ) )
16 pm3.43
 |-  ( ( ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) ) /\ ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( ( A rmY b ) - b ) ) ) -> ( A e. ( ZZ>= ` 2 ) -> ( ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) /\ ( A - 1 ) || ( ( A rmY b ) - b ) ) ) )
17 1 adantl
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> A e. ZZ )
18 17 2 syl
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> ( A - 1 ) e. ZZ )
19 eluzel2
 |-  ( A e. ( ZZ>= ` 2 ) -> 2 e. ZZ )
20 19 adantl
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> 2 e. ZZ )
21 simpr
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> A e. ( ZZ>= ` 2 ) )
22 nnz
 |-  ( b e. NN -> b e. ZZ )
23 22 adantr
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> b e. ZZ )
24 frmy
 |-  rmY : ( ( ZZ>= ` 2 ) X. ZZ ) --> ZZ
25 24 fovcl
 |-  ( ( A e. ( ZZ>= ` 2 ) /\ b e. ZZ ) -> ( A rmY b ) e. ZZ )
26 21 23 25 syl2anc
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> ( A rmY b ) e. ZZ )
27 26 17 zmulcld
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> ( ( A rmY b ) x. A ) e. ZZ )
28 20 27 zmulcld
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> ( 2 x. ( ( A rmY b ) x. A ) ) e. ZZ )
29 zmulcl
 |-  ( ( b e. ZZ /\ 1 e. ZZ ) -> ( b x. 1 ) e. ZZ )
30 23 10 29 sylancl
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> ( b x. 1 ) e. ZZ )
31 20 30 zmulcld
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> ( 2 x. ( b x. 1 ) ) e. ZZ )
32 18 28 31 3jca
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> ( ( A - 1 ) e. ZZ /\ ( 2 x. ( ( A rmY b ) x. A ) ) e. ZZ /\ ( 2 x. ( b x. 1 ) ) e. ZZ ) )
33 32 3adant3
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) /\ ( ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) /\ ( A - 1 ) || ( ( A rmY b ) - b ) ) ) -> ( ( A - 1 ) e. ZZ /\ ( 2 x. ( ( A rmY b ) x. A ) ) e. ZZ /\ ( 2 x. ( b x. 1 ) ) e. ZZ ) )
34 peano2zm
 |-  ( b e. ZZ -> ( b - 1 ) e. ZZ )
35 23 34 syl
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> ( b - 1 ) e. ZZ )
36 24 fovcl
 |-  ( ( A e. ( ZZ>= ` 2 ) /\ ( b - 1 ) e. ZZ ) -> ( A rmY ( b - 1 ) ) e. ZZ )
37 21 35 36 syl2anc
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> ( A rmY ( b - 1 ) ) e. ZZ )
38 37 35 jca
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> ( ( A rmY ( b - 1 ) ) e. ZZ /\ ( b - 1 ) e. ZZ ) )
39 38 3adant3
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) /\ ( ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) /\ ( A - 1 ) || ( ( A rmY b ) - b ) ) ) -> ( ( A rmY ( b - 1 ) ) e. ZZ /\ ( b - 1 ) e. ZZ ) )
40 18 20 20 3jca
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> ( ( A - 1 ) e. ZZ /\ 2 e. ZZ /\ 2 e. ZZ ) )
41 40 3adant3
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) /\ ( ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) /\ ( A - 1 ) || ( ( A rmY b ) - b ) ) ) -> ( ( A - 1 ) e. ZZ /\ 2 e. ZZ /\ 2 e. ZZ ) )
42 27 30 jca
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> ( ( ( A rmY b ) x. A ) e. ZZ /\ ( b x. 1 ) e. ZZ ) )
43 42 3adant3
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) /\ ( ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) /\ ( A - 1 ) || ( ( A rmY b ) - b ) ) ) -> ( ( ( A rmY b ) x. A ) e. ZZ /\ ( b x. 1 ) e. ZZ ) )
44 congid
 |-  ( ( ( A - 1 ) e. ZZ /\ 2 e. ZZ ) -> ( A - 1 ) || ( 2 - 2 ) )
45 18 20 44 syl2anc
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> ( A - 1 ) || ( 2 - 2 ) )
46 45 3adant3
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) /\ ( ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) /\ ( A - 1 ) || ( ( A rmY b ) - b ) ) ) -> ( A - 1 ) || ( 2 - 2 ) )
47 18 26 23 3jca
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> ( ( A - 1 ) e. ZZ /\ ( A rmY b ) e. ZZ /\ b e. ZZ ) )
48 47 3adant3
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) /\ ( ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) /\ ( A - 1 ) || ( ( A rmY b ) - b ) ) ) -> ( ( A - 1 ) e. ZZ /\ ( A rmY b ) e. ZZ /\ b e. ZZ ) )
49 17 10 jctir
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> ( A e. ZZ /\ 1 e. ZZ ) )
50 49 3adant3
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) /\ ( ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) /\ ( A - 1 ) || ( ( A rmY b ) - b ) ) ) -> ( A e. ZZ /\ 1 e. ZZ ) )
51 simp3r
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) /\ ( ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) /\ ( A - 1 ) || ( ( A rmY b ) - b ) ) ) -> ( A - 1 ) || ( ( A rmY b ) - b ) )
52 iddvds
 |-  ( ( A - 1 ) e. ZZ -> ( A - 1 ) || ( A - 1 ) )
53 18 52 syl
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> ( A - 1 ) || ( A - 1 ) )
54 53 3adant3
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) /\ ( ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) /\ ( A - 1 ) || ( ( A rmY b ) - b ) ) ) -> ( A - 1 ) || ( A - 1 ) )
55 congmul
 |-  ( ( ( ( A - 1 ) e. ZZ /\ ( A rmY b ) e. ZZ /\ b e. ZZ ) /\ ( A e. ZZ /\ 1 e. ZZ ) /\ ( ( A - 1 ) || ( ( A rmY b ) - b ) /\ ( A - 1 ) || ( A - 1 ) ) ) -> ( A - 1 ) || ( ( ( A rmY b ) x. A ) - ( b x. 1 ) ) )
56 48 50 51 54 55 syl112anc
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) /\ ( ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) /\ ( A - 1 ) || ( ( A rmY b ) - b ) ) ) -> ( A - 1 ) || ( ( ( A rmY b ) x. A ) - ( b x. 1 ) ) )
57 congmul
 |-  ( ( ( ( A - 1 ) e. ZZ /\ 2 e. ZZ /\ 2 e. ZZ ) /\ ( ( ( A rmY b ) x. A ) e. ZZ /\ ( b x. 1 ) e. ZZ ) /\ ( ( A - 1 ) || ( 2 - 2 ) /\ ( A - 1 ) || ( ( ( A rmY b ) x. A ) - ( b x. 1 ) ) ) ) -> ( A - 1 ) || ( ( 2 x. ( ( A rmY b ) x. A ) ) - ( 2 x. ( b x. 1 ) ) ) )
58 41 43 46 56 57 syl112anc
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) /\ ( ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) /\ ( A - 1 ) || ( ( A rmY b ) - b ) ) ) -> ( A - 1 ) || ( ( 2 x. ( ( A rmY b ) x. A ) ) - ( 2 x. ( b x. 1 ) ) ) )
59 simp3l
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) /\ ( ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) /\ ( A - 1 ) || ( ( A rmY b ) - b ) ) ) -> ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) )
60 congsub
 |-  ( ( ( ( A - 1 ) e. ZZ /\ ( 2 x. ( ( A rmY b ) x. A ) ) e. ZZ /\ ( 2 x. ( b x. 1 ) ) e. ZZ ) /\ ( ( A rmY ( b - 1 ) ) e. ZZ /\ ( b - 1 ) e. ZZ ) /\ ( ( A - 1 ) || ( ( 2 x. ( ( A rmY b ) x. A ) ) - ( 2 x. ( b x. 1 ) ) ) /\ ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) ) ) -> ( A - 1 ) || ( ( ( 2 x. ( ( A rmY b ) x. A ) ) - ( A rmY ( b - 1 ) ) ) - ( ( 2 x. ( b x. 1 ) ) - ( b - 1 ) ) ) )
61 33 39 58 59 60 syl112anc
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) /\ ( ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) /\ ( A - 1 ) || ( ( A rmY b ) - b ) ) ) -> ( A - 1 ) || ( ( ( 2 x. ( ( A rmY b ) x. A ) ) - ( A rmY ( b - 1 ) ) ) - ( ( 2 x. ( b x. 1 ) ) - ( b - 1 ) ) ) )
62 rmyluc
 |-  ( ( A e. ( ZZ>= ` 2 ) /\ b e. ZZ ) -> ( A rmY ( b + 1 ) ) = ( ( 2 x. ( ( A rmY b ) x. A ) ) - ( A rmY ( b - 1 ) ) ) )
63 21 23 62 syl2anc
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> ( A rmY ( b + 1 ) ) = ( ( 2 x. ( ( A rmY b ) x. A ) ) - ( A rmY ( b - 1 ) ) ) )
64 nncn
 |-  ( b e. NN -> b e. CC )
65 64 mulid1d
 |-  ( b e. NN -> ( b x. 1 ) = b )
66 65 oveq2d
 |-  ( b e. NN -> ( 2 x. ( b x. 1 ) ) = ( 2 x. b ) )
67 64 2timesd
 |-  ( b e. NN -> ( 2 x. b ) = ( b + b ) )
68 66 67 eqtrd
 |-  ( b e. NN -> ( 2 x. ( b x. 1 ) ) = ( b + b ) )
69 68 oveq1d
 |-  ( b e. NN -> ( ( 2 x. ( b x. 1 ) ) - ( b - 1 ) ) = ( ( b + b ) - ( b - 1 ) ) )
70 1cnd
 |-  ( b e. NN -> 1 e. CC )
71 64 64 70 pnncand
 |-  ( b e. NN -> ( ( b + b ) - ( b - 1 ) ) = ( b + 1 ) )
72 69 71 eqtr2d
 |-  ( b e. NN -> ( b + 1 ) = ( ( 2 x. ( b x. 1 ) ) - ( b - 1 ) ) )
73 72 adantr
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> ( b + 1 ) = ( ( 2 x. ( b x. 1 ) ) - ( b - 1 ) ) )
74 63 73 oveq12d
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) ) -> ( ( A rmY ( b + 1 ) ) - ( b + 1 ) ) = ( ( ( 2 x. ( ( A rmY b ) x. A ) ) - ( A rmY ( b - 1 ) ) ) - ( ( 2 x. ( b x. 1 ) ) - ( b - 1 ) ) ) )
75 74 3adant3
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) /\ ( ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) /\ ( A - 1 ) || ( ( A rmY b ) - b ) ) ) -> ( ( A rmY ( b + 1 ) ) - ( b + 1 ) ) = ( ( ( 2 x. ( ( A rmY b ) x. A ) ) - ( A rmY ( b - 1 ) ) ) - ( ( 2 x. ( b x. 1 ) ) - ( b - 1 ) ) ) )
76 61 75 breqtrrd
 |-  ( ( b e. NN /\ A e. ( ZZ>= ` 2 ) /\ ( ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) /\ ( A - 1 ) || ( ( A rmY b ) - b ) ) ) -> ( A - 1 ) || ( ( A rmY ( b + 1 ) ) - ( b + 1 ) ) )
77 76 3exp
 |-  ( b e. NN -> ( A e. ( ZZ>= ` 2 ) -> ( ( ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) /\ ( A - 1 ) || ( ( A rmY b ) - b ) ) -> ( A - 1 ) || ( ( A rmY ( b + 1 ) ) - ( b + 1 ) ) ) ) )
78 77 a2d
 |-  ( b e. NN -> ( ( A e. ( ZZ>= ` 2 ) -> ( ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) /\ ( A - 1 ) || ( ( A rmY b ) - b ) ) ) -> ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( ( A rmY ( b + 1 ) ) - ( b + 1 ) ) ) ) )
79 16 78 syl5
 |-  ( b e. NN -> ( ( ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) ) /\ ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( ( A rmY b ) - b ) ) ) -> ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( ( A rmY ( b + 1 ) ) - ( b + 1 ) ) ) ) )
80 oveq2
 |-  ( a = 0 -> ( A rmY a ) = ( A rmY 0 ) )
81 id
 |-  ( a = 0 -> a = 0 )
82 80 81 oveq12d
 |-  ( a = 0 -> ( ( A rmY a ) - a ) = ( ( A rmY 0 ) - 0 ) )
83 82 breq2d
 |-  ( a = 0 -> ( ( A - 1 ) || ( ( A rmY a ) - a ) <-> ( A - 1 ) || ( ( A rmY 0 ) - 0 ) ) )
84 83 imbi2d
 |-  ( a = 0 -> ( ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( ( A rmY a ) - a ) ) <-> ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( ( A rmY 0 ) - 0 ) ) ) )
85 oveq2
 |-  ( a = 1 -> ( A rmY a ) = ( A rmY 1 ) )
86 id
 |-  ( a = 1 -> a = 1 )
87 85 86 oveq12d
 |-  ( a = 1 -> ( ( A rmY a ) - a ) = ( ( A rmY 1 ) - 1 ) )
88 87 breq2d
 |-  ( a = 1 -> ( ( A - 1 ) || ( ( A rmY a ) - a ) <-> ( A - 1 ) || ( ( A rmY 1 ) - 1 ) ) )
89 88 imbi2d
 |-  ( a = 1 -> ( ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( ( A rmY a ) - a ) ) <-> ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( ( A rmY 1 ) - 1 ) ) ) )
90 oveq2
 |-  ( a = ( b - 1 ) -> ( A rmY a ) = ( A rmY ( b - 1 ) ) )
91 id
 |-  ( a = ( b - 1 ) -> a = ( b - 1 ) )
92 90 91 oveq12d
 |-  ( a = ( b - 1 ) -> ( ( A rmY a ) - a ) = ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) )
93 92 breq2d
 |-  ( a = ( b - 1 ) -> ( ( A - 1 ) || ( ( A rmY a ) - a ) <-> ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) ) )
94 93 imbi2d
 |-  ( a = ( b - 1 ) -> ( ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( ( A rmY a ) - a ) ) <-> ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( ( A rmY ( b - 1 ) ) - ( b - 1 ) ) ) ) )
95 oveq2
 |-  ( a = b -> ( A rmY a ) = ( A rmY b ) )
96 id
 |-  ( a = b -> a = b )
97 95 96 oveq12d
 |-  ( a = b -> ( ( A rmY a ) - a ) = ( ( A rmY b ) - b ) )
98 97 breq2d
 |-  ( a = b -> ( ( A - 1 ) || ( ( A rmY a ) - a ) <-> ( A - 1 ) || ( ( A rmY b ) - b ) ) )
99 98 imbi2d
 |-  ( a = b -> ( ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( ( A rmY a ) - a ) ) <-> ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( ( A rmY b ) - b ) ) ) )
100 oveq2
 |-  ( a = ( b + 1 ) -> ( A rmY a ) = ( A rmY ( b + 1 ) ) )
101 id
 |-  ( a = ( b + 1 ) -> a = ( b + 1 ) )
102 100 101 oveq12d
 |-  ( a = ( b + 1 ) -> ( ( A rmY a ) - a ) = ( ( A rmY ( b + 1 ) ) - ( b + 1 ) ) )
103 102 breq2d
 |-  ( a = ( b + 1 ) -> ( ( A - 1 ) || ( ( A rmY a ) - a ) <-> ( A - 1 ) || ( ( A rmY ( b + 1 ) ) - ( b + 1 ) ) ) )
104 103 imbi2d
 |-  ( a = ( b + 1 ) -> ( ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( ( A rmY a ) - a ) ) <-> ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( ( A rmY ( b + 1 ) ) - ( b + 1 ) ) ) ) )
105 oveq2
 |-  ( a = N -> ( A rmY a ) = ( A rmY N ) )
106 id
 |-  ( a = N -> a = N )
107 105 106 oveq12d
 |-  ( a = N -> ( ( A rmY a ) - a ) = ( ( A rmY N ) - N ) )
108 107 breq2d
 |-  ( a = N -> ( ( A - 1 ) || ( ( A rmY a ) - a ) <-> ( A - 1 ) || ( ( A rmY N ) - N ) ) )
109 108 imbi2d
 |-  ( a = N -> ( ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( ( A rmY a ) - a ) ) <-> ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( ( A rmY N ) - N ) ) ) )
110 9 15 79 84 89 94 99 104 109 2nn0ind
 |-  ( N e. NN0 -> ( A e. ( ZZ>= ` 2 ) -> ( A - 1 ) || ( ( A rmY N ) - N ) ) )
111 110 impcom
 |-  ( ( A e. ( ZZ>= ` 2 ) /\ N e. NN0 ) -> ( A - 1 ) || ( ( A rmY N ) - N ) )