| Step |
Hyp |
Ref |
Expression |
| 1 |
|
2nn |
|- 2 e. NN |
| 2 |
|
simpl |
|- ( ( A e. NN /\ N e. ZZ ) -> A e. NN ) |
| 3 |
|
nnmulcl |
|- ( ( 2 e. NN /\ A e. NN ) -> ( 2 x. A ) e. NN ) |
| 4 |
1 2 3
|
sylancr |
|- ( ( A e. NN /\ N e. ZZ ) -> ( 2 x. A ) e. NN ) |
| 5 |
|
simpr |
|- ( ( A e. NN /\ N e. ZZ ) -> N e. ZZ ) |
| 6 |
|
congrep |
|- ( ( ( 2 x. A ) e. NN /\ N e. ZZ ) -> E. b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) ( 2 x. A ) || ( b - N ) ) |
| 7 |
4 5 6
|
syl2anc |
|- ( ( A e. NN /\ N e. ZZ ) -> E. b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) ( 2 x. A ) || ( b - N ) ) |
| 8 |
|
elfzelz |
|- ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) -> b e. ZZ ) |
| 9 |
8
|
zred |
|- ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) -> b e. RR ) |
| 10 |
9
|
ad2antrl |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> b e. RR ) |
| 11 |
|
nnre |
|- ( A e. NN -> A e. RR ) |
| 12 |
11
|
ad2antrr |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> A e. RR ) |
| 13 |
|
elfzle1 |
|- ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) -> 0 <_ b ) |
| 14 |
13
|
ad2antrl |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> 0 <_ b ) |
| 15 |
14
|
anim1i |
|- ( ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) /\ b <_ A ) -> ( 0 <_ b /\ b <_ A ) ) |
| 16 |
8
|
ad2antrl |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> b e. ZZ ) |
| 17 |
|
0zd |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> 0 e. ZZ ) |
| 18 |
|
nnz |
|- ( A e. NN -> A e. ZZ ) |
| 19 |
18
|
ad2antrr |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> A e. ZZ ) |
| 20 |
|
elfz |
|- ( ( b e. ZZ /\ 0 e. ZZ /\ A e. ZZ ) -> ( b e. ( 0 ... A ) <-> ( 0 <_ b /\ b <_ A ) ) ) |
| 21 |
16 17 19 20
|
syl3anc |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> ( b e. ( 0 ... A ) <-> ( 0 <_ b /\ b <_ A ) ) ) |
| 22 |
21
|
adantr |
|- ( ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) /\ b <_ A ) -> ( b e. ( 0 ... A ) <-> ( 0 <_ b /\ b <_ A ) ) ) |
| 23 |
15 22
|
mpbird |
|- ( ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) /\ b <_ A ) -> b e. ( 0 ... A ) ) |
| 24 |
|
simplrr |
|- ( ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) /\ b <_ A ) -> ( 2 x. A ) || ( b - N ) ) |
| 25 |
24
|
orcd |
|- ( ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) /\ b <_ A ) -> ( ( 2 x. A ) || ( b - N ) \/ ( 2 x. A ) || ( b - -u N ) ) ) |
| 26 |
|
id |
|- ( a = b -> a = b ) |
| 27 |
|
eqidd |
|- ( a = b -> N = N ) |
| 28 |
26 27
|
acongeq12d |
|- ( a = b -> ( ( ( 2 x. A ) || ( a - N ) \/ ( 2 x. A ) || ( a - -u N ) ) <-> ( ( 2 x. A ) || ( b - N ) \/ ( 2 x. A ) || ( b - -u N ) ) ) ) |
| 29 |
28
|
rspcev |
|- ( ( b e. ( 0 ... A ) /\ ( ( 2 x. A ) || ( b - N ) \/ ( 2 x. A ) || ( b - -u N ) ) ) -> E. a e. ( 0 ... A ) ( ( 2 x. A ) || ( a - N ) \/ ( 2 x. A ) || ( a - -u N ) ) ) |
| 30 |
23 25 29
|
syl2anc |
|- ( ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) /\ b <_ A ) -> E. a e. ( 0 ... A ) ( ( 2 x. A ) || ( a - N ) \/ ( 2 x. A ) || ( a - -u N ) ) ) |
| 31 |
|
simplll |
|- ( ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) /\ A <_ b ) -> A e. NN ) |
| 32 |
|
simplrl |
|- ( ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) /\ A <_ b ) -> b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) ) |
| 33 |
|
simpr |
|- ( ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) /\ A <_ b ) -> A <_ b ) |
| 34 |
9
|
3ad2ant2 |
|- ( ( A e. NN /\ b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ A <_ b ) -> b e. RR ) |
| 35 |
|
2re |
|- 2 e. RR |
| 36 |
|
remulcl |
|- ( ( 2 e. RR /\ A e. RR ) -> ( 2 x. A ) e. RR ) |
| 37 |
35 11 36
|
sylancr |
|- ( A e. NN -> ( 2 x. A ) e. RR ) |
| 38 |
37
|
3ad2ant1 |
|- ( ( A e. NN /\ b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ A <_ b ) -> ( 2 x. A ) e. RR ) |
| 39 |
|
0zd |
|- ( ( A e. NN /\ b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ A <_ b ) -> 0 e. ZZ ) |
| 40 |
|
2z |
|- 2 e. ZZ |
| 41 |
|
zmulcl |
|- ( ( 2 e. ZZ /\ A e. ZZ ) -> ( 2 x. A ) e. ZZ ) |
| 42 |
40 18 41
|
sylancr |
|- ( A e. NN -> ( 2 x. A ) e. ZZ ) |
| 43 |
42
|
3ad2ant1 |
|- ( ( A e. NN /\ b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ A <_ b ) -> ( 2 x. A ) e. ZZ ) |
| 44 |
|
simp2 |
|- ( ( A e. NN /\ b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ A <_ b ) -> b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) ) |
| 45 |
|
elfzm11 |
|- ( ( 0 e. ZZ /\ ( 2 x. A ) e. ZZ ) -> ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) <-> ( b e. ZZ /\ 0 <_ b /\ b < ( 2 x. A ) ) ) ) |
| 46 |
45
|
biimpa |
|- ( ( ( 0 e. ZZ /\ ( 2 x. A ) e. ZZ ) /\ b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) ) -> ( b e. ZZ /\ 0 <_ b /\ b < ( 2 x. A ) ) ) |
| 47 |
39 43 44 46
|
syl21anc |
|- ( ( A e. NN /\ b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ A <_ b ) -> ( b e. ZZ /\ 0 <_ b /\ b < ( 2 x. A ) ) ) |
| 48 |
47
|
simp3d |
|- ( ( A e. NN /\ b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ A <_ b ) -> b < ( 2 x. A ) ) |
| 49 |
34 38 48
|
ltled |
|- ( ( A e. NN /\ b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ A <_ b ) -> b <_ ( 2 x. A ) ) |
| 50 |
38 34
|
subge0d |
|- ( ( A e. NN /\ b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ A <_ b ) -> ( 0 <_ ( ( 2 x. A ) - b ) <-> b <_ ( 2 x. A ) ) ) |
| 51 |
49 50
|
mpbird |
|- ( ( A e. NN /\ b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ A <_ b ) -> 0 <_ ( ( 2 x. A ) - b ) ) |
| 52 |
11
|
3ad2ant1 |
|- ( ( A e. NN /\ b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ A <_ b ) -> A e. RR ) |
| 53 |
|
nncn |
|- ( A e. NN -> A e. CC ) |
| 54 |
|
2times |
|- ( A e. CC -> ( 2 x. A ) = ( A + A ) ) |
| 55 |
54
|
oveq1d |
|- ( A e. CC -> ( ( 2 x. A ) - A ) = ( ( A + A ) - A ) ) |
| 56 |
|
pncan2 |
|- ( ( A e. CC /\ A e. CC ) -> ( ( A + A ) - A ) = A ) |
| 57 |
56
|
anidms |
|- ( A e. CC -> ( ( A + A ) - A ) = A ) |
| 58 |
55 57
|
eqtrd |
|- ( A e. CC -> ( ( 2 x. A ) - A ) = A ) |
| 59 |
53 58
|
syl |
|- ( A e. NN -> ( ( 2 x. A ) - A ) = A ) |
| 60 |
59
|
3ad2ant1 |
|- ( ( A e. NN /\ b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ A <_ b ) -> ( ( 2 x. A ) - A ) = A ) |
| 61 |
|
simp3 |
|- ( ( A e. NN /\ b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ A <_ b ) -> A <_ b ) |
| 62 |
60 61
|
eqbrtrd |
|- ( ( A e. NN /\ b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ A <_ b ) -> ( ( 2 x. A ) - A ) <_ b ) |
| 63 |
38 52 34 62
|
subled |
|- ( ( A e. NN /\ b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ A <_ b ) -> ( ( 2 x. A ) - b ) <_ A ) |
| 64 |
51 63
|
jca |
|- ( ( A e. NN /\ b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ A <_ b ) -> ( 0 <_ ( ( 2 x. A ) - b ) /\ ( ( 2 x. A ) - b ) <_ A ) ) |
| 65 |
31 32 33 64
|
syl3anc |
|- ( ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) /\ A <_ b ) -> ( 0 <_ ( ( 2 x. A ) - b ) /\ ( ( 2 x. A ) - b ) <_ A ) ) |
| 66 |
40 19 41
|
sylancr |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> ( 2 x. A ) e. ZZ ) |
| 67 |
66 16
|
zsubcld |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> ( ( 2 x. A ) - b ) e. ZZ ) |
| 68 |
|
elfz |
|- ( ( ( ( 2 x. A ) - b ) e. ZZ /\ 0 e. ZZ /\ A e. ZZ ) -> ( ( ( 2 x. A ) - b ) e. ( 0 ... A ) <-> ( 0 <_ ( ( 2 x. A ) - b ) /\ ( ( 2 x. A ) - b ) <_ A ) ) ) |
| 69 |
67 17 19 68
|
syl3anc |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> ( ( ( 2 x. A ) - b ) e. ( 0 ... A ) <-> ( 0 <_ ( ( 2 x. A ) - b ) /\ ( ( 2 x. A ) - b ) <_ A ) ) ) |
| 70 |
69
|
adantr |
|- ( ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) /\ A <_ b ) -> ( ( ( 2 x. A ) - b ) e. ( 0 ... A ) <-> ( 0 <_ ( ( 2 x. A ) - b ) /\ ( ( 2 x. A ) - b ) <_ A ) ) ) |
| 71 |
65 70
|
mpbird |
|- ( ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) /\ A <_ b ) -> ( ( 2 x. A ) - b ) e. ( 0 ... A ) ) |
| 72 |
|
simplr |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> N e. ZZ ) |
| 73 |
|
simprr |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> ( 2 x. A ) || ( b - N ) ) |
| 74 |
|
congsym |
|- ( ( ( ( 2 x. A ) e. ZZ /\ b e. ZZ ) /\ ( N e. ZZ /\ ( 2 x. A ) || ( b - N ) ) ) -> ( 2 x. A ) || ( N - b ) ) |
| 75 |
66 16 72 73 74
|
syl22anc |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> ( 2 x. A ) || ( N - b ) ) |
| 76 |
72 16
|
zsubcld |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> ( N - b ) e. ZZ ) |
| 77 |
|
dvdsadd |
|- ( ( ( 2 x. A ) e. ZZ /\ ( N - b ) e. ZZ ) -> ( ( 2 x. A ) || ( N - b ) <-> ( 2 x. A ) || ( ( 2 x. A ) + ( N - b ) ) ) ) |
| 78 |
66 76 77
|
syl2anc |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> ( ( 2 x. A ) || ( N - b ) <-> ( 2 x. A ) || ( ( 2 x. A ) + ( N - b ) ) ) ) |
| 79 |
75 78
|
mpbid |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> ( 2 x. A ) || ( ( 2 x. A ) + ( N - b ) ) ) |
| 80 |
67
|
zcnd |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> ( ( 2 x. A ) - b ) e. CC ) |
| 81 |
|
zcn |
|- ( N e. ZZ -> N e. CC ) |
| 82 |
81
|
ad2antlr |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> N e. CC ) |
| 83 |
80 82
|
subnegd |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> ( ( ( 2 x. A ) - b ) - -u N ) = ( ( ( 2 x. A ) - b ) + N ) ) |
| 84 |
66
|
zcnd |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> ( 2 x. A ) e. CC ) |
| 85 |
10
|
recnd |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> b e. CC ) |
| 86 |
84 85 82
|
subadd23d |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> ( ( ( 2 x. A ) - b ) + N ) = ( ( 2 x. A ) + ( N - b ) ) ) |
| 87 |
83 86
|
eqtrd |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> ( ( ( 2 x. A ) - b ) - -u N ) = ( ( 2 x. A ) + ( N - b ) ) ) |
| 88 |
79 87
|
breqtrrd |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> ( 2 x. A ) || ( ( ( 2 x. A ) - b ) - -u N ) ) |
| 89 |
88
|
adantr |
|- ( ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) /\ A <_ b ) -> ( 2 x. A ) || ( ( ( 2 x. A ) - b ) - -u N ) ) |
| 90 |
89
|
olcd |
|- ( ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) /\ A <_ b ) -> ( ( 2 x. A ) || ( ( ( 2 x. A ) - b ) - N ) \/ ( 2 x. A ) || ( ( ( 2 x. A ) - b ) - -u N ) ) ) |
| 91 |
|
id |
|- ( a = ( ( 2 x. A ) - b ) -> a = ( ( 2 x. A ) - b ) ) |
| 92 |
|
eqidd |
|- ( a = ( ( 2 x. A ) - b ) -> N = N ) |
| 93 |
91 92
|
acongeq12d |
|- ( a = ( ( 2 x. A ) - b ) -> ( ( ( 2 x. A ) || ( a - N ) \/ ( 2 x. A ) || ( a - -u N ) ) <-> ( ( 2 x. A ) || ( ( ( 2 x. A ) - b ) - N ) \/ ( 2 x. A ) || ( ( ( 2 x. A ) - b ) - -u N ) ) ) ) |
| 94 |
93
|
rspcev |
|- ( ( ( ( 2 x. A ) - b ) e. ( 0 ... A ) /\ ( ( 2 x. A ) || ( ( ( 2 x. A ) - b ) - N ) \/ ( 2 x. A ) || ( ( ( 2 x. A ) - b ) - -u N ) ) ) -> E. a e. ( 0 ... A ) ( ( 2 x. A ) || ( a - N ) \/ ( 2 x. A ) || ( a - -u N ) ) ) |
| 95 |
71 90 94
|
syl2anc |
|- ( ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) /\ A <_ b ) -> E. a e. ( 0 ... A ) ( ( 2 x. A ) || ( a - N ) \/ ( 2 x. A ) || ( a - -u N ) ) ) |
| 96 |
10 12 30 95
|
lecasei |
|- ( ( ( A e. NN /\ N e. ZZ ) /\ ( b e. ( 0 ... ( ( 2 x. A ) - 1 ) ) /\ ( 2 x. A ) || ( b - N ) ) ) -> E. a e. ( 0 ... A ) ( ( 2 x. A ) || ( a - N ) \/ ( 2 x. A ) || ( a - -u N ) ) ) |
| 97 |
7 96
|
rexlimddv |
|- ( ( A e. NN /\ N e. ZZ ) -> E. a e. ( 0 ... A ) ( ( 2 x. A ) || ( a - N ) \/ ( 2 x. A ) || ( a - -u N ) ) ) |