Metamath Proof Explorer


Theorem nohalf

Description: An explicit expression for one half. This theorem avoids the axiom of infinity. (Contributed by Scott Fenton, 23-Jul-2025)

Ref Expression
Assertion nohalf Could not format assertion : No typesetting found for |- ( 1s /su 2s ) = ( { 0s } |s { 1s } ) with typecode |-

Proof

Step Hyp Ref Expression
1 snex 0 s V
2 1 a1i 0 s V
3 snex 1 s V
4 3 a1i 1 s V
5 0sno 0 s No
6 5 a1i 0 s No
7 6 snssd 0 s No
8 1sno 1 s No
9 snssi 1 s No 1 s No
10 8 9 mp1i 1 s No
11 velsn x 0 s x = 0 s
12 velsn y 1 s y = 1 s
13 0slt1s 0 s < s 1 s
14 breq12 x = 0 s y = 1 s x < s y 0 s < s 1 s
15 13 14 mpbiri x = 0 s y = 1 s x < s y
16 11 12 15 syl2anb x 0 s y 1 s x < s y
17 16 3adant1 x 0 s y 1 s x < s y
18 2 4 7 10 17 ssltd 0 s s 1 s
19 18 scutcld 0 s | s 1 s No
20 19 mptru 0 s | s 1 s No
21 no2times Could not format ( ( { 0s } |s { 1s } ) e. No -> ( 2s x.s ( { 0s } |s { 1s } ) ) = ( ( { 0s } |s { 1s } ) +s ( { 0s } |s { 1s } ) ) ) : No typesetting found for |- ( ( { 0s } |s { 1s } ) e. No -> ( 2s x.s ( { 0s } |s { 1s } ) ) = ( ( { 0s } |s { 1s } ) +s ( { 0s } |s { 1s } ) ) ) with typecode |-
22 20 21 ax-mp Could not format ( 2s x.s ( { 0s } |s { 1s } ) ) = ( ( { 0s } |s { 1s } ) +s ( { 0s } |s { 1s } ) ) : No typesetting found for |- ( 2s x.s ( { 0s } |s { 1s } ) ) = ( ( { 0s } |s { 1s } ) +s ( { 0s } |s { 1s } ) ) with typecode |-
23 eqidd 0 s | s 1 s = 0 s | s 1 s
24 18 18 23 23 addsunif 0 s | s 1 s + s 0 s | s 1 s = x | y 0 s x = y + s 0 s | s 1 s x | y 0 s x = 0 s | s 1 s + s y | s x | y 1 s x = y + s 0 s | s 1 s x | y 1 s x = 0 s | s 1 s + s y
25 24 mptru 0 s | s 1 s + s 0 s | s 1 s = x | y 0 s x = y + s 0 s | s 1 s x | y 0 s x = 0 s | s 1 s + s y | s x | y 1 s x = y + s 0 s | s 1 s x | y 1 s x = 0 s | s 1 s + s y
26 5 elexi 0 s V
27 oveq1 y = 0 s y + s 0 s | s 1 s = 0 s + s 0 s | s 1 s
28 addslid 0 s | s 1 s No 0 s + s 0 s | s 1 s = 0 s | s 1 s
29 20 28 ax-mp 0 s + s 0 s | s 1 s = 0 s | s 1 s
30 27 29 eqtrdi y = 0 s y + s 0 s | s 1 s = 0 s | s 1 s
31 30 eqeq2d y = 0 s x = y + s 0 s | s 1 s x = 0 s | s 1 s
32 26 31 rexsn y 0 s x = y + s 0 s | s 1 s x = 0 s | s 1 s
33 32 abbii x | y 0 s x = y + s 0 s | s 1 s = x | x = 0 s | s 1 s
34 df-sn 0 s | s 1 s = x | x = 0 s | s 1 s
35 33 34 eqtr4i x | y 0 s x = y + s 0 s | s 1 s = 0 s | s 1 s
36 oveq2 y = 0 s 0 s | s 1 s + s y = 0 s | s 1 s + s 0 s
37 addsrid 0 s | s 1 s No 0 s | s 1 s + s 0 s = 0 s | s 1 s
38 20 37 ax-mp 0 s | s 1 s + s 0 s = 0 s | s 1 s
39 36 38 eqtrdi y = 0 s 0 s | s 1 s + s y = 0 s | s 1 s
40 39 eqeq2d y = 0 s x = 0 s | s 1 s + s y x = 0 s | s 1 s
41 26 40 rexsn y 0 s x = 0 s | s 1 s + s y x = 0 s | s 1 s
42 41 abbii x | y 0 s x = 0 s | s 1 s + s y = x | x = 0 s | s 1 s
43 42 34 eqtr4i x | y 0 s x = 0 s | s 1 s + s y = 0 s | s 1 s
44 35 43 uneq12i x | y 0 s x = y + s 0 s | s 1 s x | y 0 s x = 0 s | s 1 s + s y = 0 s | s 1 s 0 s | s 1 s
45 unidm 0 s | s 1 s 0 s | s 1 s = 0 s | s 1 s
46 44 45 eqtri x | y 0 s x = y + s 0 s | s 1 s x | y 0 s x = 0 s | s 1 s + s y = 0 s | s 1 s
47 8 elexi 1 s V
48 oveq1 y = 1 s y + s 0 s | s 1 s = 1 s + s 0 s | s 1 s
49 addscom 1 s No 0 s | s 1 s No 1 s + s 0 s | s 1 s = 0 s | s 1 s + s 1 s
50 8 20 49 mp2an 1 s + s 0 s | s 1 s = 0 s | s 1 s + s 1 s
51 48 50 eqtrdi y = 1 s y + s 0 s | s 1 s = 0 s | s 1 s + s 1 s
52 51 eqeq2d y = 1 s x = y + s 0 s | s 1 s x = 0 s | s 1 s + s 1 s
53 47 52 rexsn y 1 s x = y + s 0 s | s 1 s x = 0 s | s 1 s + s 1 s
54 53 abbii x | y 1 s x = y + s 0 s | s 1 s = x | x = 0 s | s 1 s + s 1 s
55 df-sn 0 s | s 1 s + s 1 s = x | x = 0 s | s 1 s + s 1 s
56 54 55 eqtr4i x | y 1 s x = y + s 0 s | s 1 s = 0 s | s 1 s + s 1 s
57 oveq2 y = 1 s 0 s | s 1 s + s y = 0 s | s 1 s + s 1 s
58 57 eqeq2d y = 1 s x = 0 s | s 1 s + s y x = 0 s | s 1 s + s 1 s
59 47 58 rexsn y 1 s x = 0 s | s 1 s + s y x = 0 s | s 1 s + s 1 s
60 59 abbii x | y 1 s x = 0 s | s 1 s + s y = x | x = 0 s | s 1 s + s 1 s
61 60 55 eqtr4i x | y 1 s x = 0 s | s 1 s + s y = 0 s | s 1 s + s 1 s
62 56 61 uneq12i x | y 1 s x = y + s 0 s | s 1 s x | y 1 s x = 0 s | s 1 s + s y = 0 s | s 1 s + s 1 s 0 s | s 1 s + s 1 s
63 unidm 0 s | s 1 s + s 1 s 0 s | s 1 s + s 1 s = 0 s | s 1 s + s 1 s
64 62 63 eqtri x | y 1 s x = y + s 0 s | s 1 s x | y 1 s x = 0 s | s 1 s + s y = 0 s | s 1 s + s 1 s
65 46 64 oveq12i x | y 0 s x = y + s 0 s | s 1 s x | y 0 s x = 0 s | s 1 s + s y | s x | y 1 s x = y + s 0 s | s 1 s x | y 1 s x = 0 s | s 1 s + s y = 0 s | s 1 s | s 0 s | s 1 s + s 1 s
66 ral0 x 0 s | s 1 s | s 0 s | s 1 s + s 1 s < s x
67 slerflex 1 s No 1 s s 1 s
68 8 67 ax-mp 1 s s 1 s
69 breq1 y = 1 s y s 1 s 1 s s 1 s
70 47 69 rexsn y 1 s y s 1 s 1 s s 1 s
71 68 70 mpbir y 1 s y s 1 s
72 71 olci x 0 s 0 s | s 1 s s x y 1 s y s 1 s
73 18 mptru 0 s s 1 s
74 snelpwi 0 s No 0 s 𝒫 No
75 5 74 ax-mp 0 s 𝒫 No
76 nulssgt 0 s 𝒫 No 0 s s
77 75 76 ax-mp 0 s s
78 eqid 0 s | s 1 s = 0 s | s 1 s
79 df-1s 1 s = 0 s | s
80 sltrec 0 s s 1 s 0 s s 0 s | s 1 s = 0 s | s 1 s 1 s = 0 s | s 0 s | s 1 s < s 1 s x 0 s 0 s | s 1 s s x y 1 s y s 1 s
81 73 77 78 79 80 mp4an 0 s | s 1 s < s 1 s x 0 s 0 s | s 1 s s x y 1 s y s 1 s
82 72 81 mpbir 0 s | s 1 s < s 1 s
83 ovex 0 s | s 1 s V
84 breq1 y = 0 s | s 1 s y < s 1 s 0 s | s 1 s < s 1 s
85 83 84 ralsn y 0 s | s 1 s y < s 1 s 0 s | s 1 s < s 1 s
86 82 85 mpbir y 0 s | s 1 s y < s 1 s
87 snex 0 s | s 1 s V
88 87 a1i 0 s | s 1 s V
89 snex 0 s | s 1 s + s 1 s V
90 89 a1i 0 s | s 1 s + s 1 s V
91 19 snssd 0 s | s 1 s No
92 8 a1i 1 s No
93 19 92 addscld 0 s | s 1 s + s 1 s No
94 93 snssd 0 s | s 1 s + s 1 s No
95 velsn x 0 s | s 1 s x = 0 s | s 1 s
96 velsn y 0 s | s 1 s + s 1 s y = 0 s | s 1 s + s 1 s
97 sltadd2 0 s No 1 s No 0 s | s 1 s No 0 s < s 1 s 0 s | s 1 s + s 0 s < s 0 s | s 1 s + s 1 s
98 5 8 20 97 mp3an 0 s < s 1 s 0 s | s 1 s + s 0 s < s 0 s | s 1 s + s 1 s
99 13 98 mpbi 0 s | s 1 s + s 0 s < s 0 s | s 1 s + s 1 s
100 38 99 eqbrtrri 0 s | s 1 s < s 0 s | s 1 s + s 1 s
101 breq12 x = 0 s | s 1 s y = 0 s | s 1 s + s 1 s x < s y 0 s | s 1 s < s 0 s | s 1 s + s 1 s
102 100 101 mpbiri x = 0 s | s 1 s y = 0 s | s 1 s + s 1 s x < s y
103 95 96 102 syl2anb x 0 s | s 1 s y 0 s | s 1 s + s 1 s x < s y
104 103 3adant1 x 0 s | s 1 s y 0 s | s 1 s + s 1 s x < s y
105 88 90 91 94 104 ssltd 0 s | s 1 s s 0 s | s 1 s + s 1 s
106 105 mptru 0 s | s 1 s s 0 s | s 1 s + s 1 s
107 eqid 0 s | s 1 s | s 0 s | s 1 s + s 1 s = 0 s | s 1 s | s 0 s | s 1 s + s 1 s
108 slerec 0 s | s 1 s s 0 s | s 1 s + s 1 s 0 s s 0 s | s 1 s | s 0 s | s 1 s + s 1 s = 0 s | s 1 s | s 0 s | s 1 s + s 1 s 1 s = 0 s | s 0 s | s 1 s | s 0 s | s 1 s + s 1 s s 1 s x 0 s | s 1 s | s 0 s | s 1 s + s 1 s < s x y 0 s | s 1 s y < s 1 s
109 106 77 107 79 108 mp4an 0 s | s 1 s | s 0 s | s 1 s + s 1 s s 1 s x 0 s | s 1 s | s 0 s | s 1 s + s 1 s < s x y 0 s | s 1 s y < s 1 s
110 66 86 109 mpbir2an 0 s | s 1 s | s 0 s | s 1 s + s 1 s s 1 s
111 addslid 1 s No 0 s + s 1 s = 1 s
112 8 111 ax-mp 0 s + s 1 s = 1 s
113 slerflex 0 s No 0 s s 0 s
114 5 113 ax-mp 0 s s 0 s
115 breq2 x = 0 s 0 s s x 0 s s 0 s
116 26 115 rexsn x 0 s 0 s s x 0 s s 0 s
117 114 116 mpbir x 0 s 0 s s x
118 117 orci x 0 s 0 s s x y y s 0 s | s 1 s
119 0elpw 𝒫 No
120 nulssgt 𝒫 No s
121 119 120 ax-mp s
122 df-0s 0 s = | s
123 sltrec s 0 s s 1 s 0 s = | s 0 s | s 1 s = 0 s | s 1 s 0 s < s 0 s | s 1 s x 0 s 0 s s x y y s 0 s | s 1 s
124 121 73 122 78 123 mp4an 0 s < s 0 s | s 1 s x 0 s 0 s s x y y s 0 s | s 1 s
125 118 124 mpbir 0 s < s 0 s | s 1 s
126 sltadd1 0 s No 0 s | s 1 s No 1 s No 0 s < s 0 s | s 1 s 0 s + s 1 s < s 0 s | s 1 s + s 1 s
127 5 20 8 126 mp3an 0 s < s 0 s | s 1 s 0 s + s 1 s < s 0 s | s 1 s + s 1 s
128 125 127 mpbi 0 s + s 1 s < s 0 s | s 1 s + s 1 s
129 112 128 eqbrtrri 1 s < s 0 s | s 1 s + s 1 s
130 ovex 0 s | s 1 s + s 1 s V
131 breq2 y = 0 s | s 1 s + s 1 s 1 s < s y 1 s < s 0 s | s 1 s + s 1 s
132 130 131 ralsn y 0 s | s 1 s + s 1 s 1 s < s y 1 s < s 0 s | s 1 s + s 1 s
133 129 132 mpbir y 0 s | s 1 s + s 1 s 1 s < s y
134 breq2 x = 1 s 0 s < s x 0 s < s 1 s
135 47 134 ralsn x 1 s 0 s < s x 0 s < s 1 s
136 13 135 mpbir x 1 s 0 s < s x
137 ral0 y y < s 0 s | s 1 s
138 slerec s 0 s s 1 s 0 s = | s 0 s | s 1 s = 0 s | s 1 s 0 s s 0 s | s 1 s x 1 s 0 s < s x y y < s 0 s | s 1 s
139 121 73 122 78 138 mp4an 0 s s 0 s | s 1 s x 1 s 0 s < s x y y < s 0 s | s 1 s
140 136 137 139 mpbir2an 0 s s 0 s | s 1 s
141 breq2 x = 0 s | s 1 s 0 s s x 0 s s 0 s | s 1 s
142 83 141 rexsn x 0 s | s 1 s 0 s s x 0 s s 0 s | s 1 s
143 140 142 mpbir x 0 s | s 1 s 0 s s x
144 143 orci x 0 s | s 1 s 0 s s x y y s 0 s | s 1 s | s 0 s | s 1 s + s 1 s
145 sltrec s 0 s | s 1 s s 0 s | s 1 s + s 1 s 0 s = | s 0 s | s 1 s | s 0 s | s 1 s + s 1 s = 0 s | s 1 s | s 0 s | s 1 s + s 1 s 0 s < s 0 s | s 1 s | s 0 s | s 1 s + s 1 s x 0 s | s 1 s 0 s s x y y s 0 s | s 1 s | s 0 s | s 1 s + s 1 s
146 121 106 122 107 145 mp4an 0 s < s 0 s | s 1 s | s 0 s | s 1 s + s 1 s x 0 s | s 1 s 0 s s x y y s 0 s | s 1 s | s 0 s | s 1 s + s 1 s
147 144 146 mpbir 0 s < s 0 s | s 1 s | s 0 s | s 1 s + s 1 s
148 breq1 x = 0 s x < s 0 s | s 1 s | s 0 s | s 1 s + s 1 s 0 s < s 0 s | s 1 s | s 0 s | s 1 s + s 1 s
149 26 148 ralsn x 0 s x < s 0 s | s 1 s | s 0 s | s 1 s + s 1 s 0 s < s 0 s | s 1 s | s 0 s | s 1 s + s 1 s
150 147 149 mpbir x 0 s x < s 0 s | s 1 s | s 0 s | s 1 s + s 1 s
151 slerec 0 s s 0 s | s 1 s s 0 s | s 1 s + s 1 s 1 s = 0 s | s 0 s | s 1 s | s 0 s | s 1 s + s 1 s = 0 s | s 1 s | s 0 s | s 1 s + s 1 s 1 s s 0 s | s 1 s | s 0 s | s 1 s + s 1 s y 0 s | s 1 s + s 1 s 1 s < s y x 0 s x < s 0 s | s 1 s | s 0 s | s 1 s + s 1 s
152 77 106 79 107 151 mp4an 1 s s 0 s | s 1 s | s 0 s | s 1 s + s 1 s y 0 s | s 1 s + s 1 s 1 s < s y x 0 s x < s 0 s | s 1 s | s 0 s | s 1 s + s 1 s
153 133 150 152 mpbir2an 1 s s 0 s | s 1 s | s 0 s | s 1 s + s 1 s
154 105 scutcld 0 s | s 1 s | s 0 s | s 1 s + s 1 s No
155 154 mptru 0 s | s 1 s | s 0 s | s 1 s + s 1 s No
156 sletri3 0 s | s 1 s | s 0 s | s 1 s + s 1 s No 1 s No 0 s | s 1 s | s 0 s | s 1 s + s 1 s = 1 s 0 s | s 1 s | s 0 s | s 1 s + s 1 s s 1 s 1 s s 0 s | s 1 s | s 0 s | s 1 s + s 1 s
157 155 8 156 mp2an 0 s | s 1 s | s 0 s | s 1 s + s 1 s = 1 s 0 s | s 1 s | s 0 s | s 1 s + s 1 s s 1 s 1 s s 0 s | s 1 s | s 0 s | s 1 s + s 1 s
158 110 153 157 mpbir2an 0 s | s 1 s | s 0 s | s 1 s + s 1 s = 1 s
159 65 158 eqtri x | y 0 s x = y + s 0 s | s 1 s x | y 0 s x = 0 s | s 1 s + s y | s x | y 1 s x = y + s 0 s | s 1 s x | y 1 s x = 0 s | s 1 s + s y = 1 s
160 25 159 eqtri 0 s | s 1 s + s 0 s | s 1 s = 1 s
161 22 160 eqtri Could not format ( 2s x.s ( { 0s } |s { 1s } ) ) = 1s : No typesetting found for |- ( 2s x.s ( { 0s } |s { 1s } ) ) = 1s with typecode |-
162 2sno Could not format 2s e. No : No typesetting found for |- 2s e. No with typecode |-
163 2ne0s Could not format 2s =/= 0s : No typesetting found for |- 2s =/= 0s with typecode |-
164 162 163 pm3.2i Could not format ( 2s e. No /\ 2s =/= 0s ) : No typesetting found for |- ( 2s e. No /\ 2s =/= 0s ) with typecode |-
165 8 20 164 3pm3.2i Could not format ( 1s e. No /\ ( { 0s } |s { 1s } ) e. No /\ ( 2s e. No /\ 2s =/= 0s ) ) : No typesetting found for |- ( 1s e. No /\ ( { 0s } |s { 1s } ) e. No /\ ( 2s e. No /\ 2s =/= 0s ) ) with typecode |-
166 oveq2 Could not format ( x = ( { 0s } |s { 1s } ) -> ( 2s x.s x ) = ( 2s x.s ( { 0s } |s { 1s } ) ) ) : No typesetting found for |- ( x = ( { 0s } |s { 1s } ) -> ( 2s x.s x ) = ( 2s x.s ( { 0s } |s { 1s } ) ) ) with typecode |-
167 166 eqeq1d Could not format ( x = ( { 0s } |s { 1s } ) -> ( ( 2s x.s x ) = 1s <-> ( 2s x.s ( { 0s } |s { 1s } ) ) = 1s ) ) : No typesetting found for |- ( x = ( { 0s } |s { 1s } ) -> ( ( 2s x.s x ) = 1s <-> ( 2s x.s ( { 0s } |s { 1s } ) ) = 1s ) ) with typecode |-
168 167 rspcev Could not format ( ( ( { 0s } |s { 1s } ) e. No /\ ( 2s x.s ( { 0s } |s { 1s } ) ) = 1s ) -> E. x e. No ( 2s x.s x ) = 1s ) : No typesetting found for |- ( ( ( { 0s } |s { 1s } ) e. No /\ ( 2s x.s ( { 0s } |s { 1s } ) ) = 1s ) -> E. x e. No ( 2s x.s x ) = 1s ) with typecode |-
169 20 161 168 mp2an Could not format E. x e. No ( 2s x.s x ) = 1s : No typesetting found for |- E. x e. No ( 2s x.s x ) = 1s with typecode |-
170 divsmulw Could not format ( ( ( 1s e. No /\ ( { 0s } |s { 1s } ) e. No /\ ( 2s e. No /\ 2s =/= 0s ) ) /\ E. x e. No ( 2s x.s x ) = 1s ) -> ( ( 1s /su 2s ) = ( { 0s } |s { 1s } ) <-> ( 2s x.s ( { 0s } |s { 1s } ) ) = 1s ) ) : No typesetting found for |- ( ( ( 1s e. No /\ ( { 0s } |s { 1s } ) e. No /\ ( 2s e. No /\ 2s =/= 0s ) ) /\ E. x e. No ( 2s x.s x ) = 1s ) -> ( ( 1s /su 2s ) = ( { 0s } |s { 1s } ) <-> ( 2s x.s ( { 0s } |s { 1s } ) ) = 1s ) ) with typecode |-
171 165 169 170 mp2an Could not format ( ( 1s /su 2s ) = ( { 0s } |s { 1s } ) <-> ( 2s x.s ( { 0s } |s { 1s } ) ) = 1s ) : No typesetting found for |- ( ( 1s /su 2s ) = ( { 0s } |s { 1s } ) <-> ( 2s x.s ( { 0s } |s { 1s } ) ) = 1s ) with typecode |-
172 161 171 mpbir Could not format ( 1s /su 2s ) = ( { 0s } |s { 1s } ) : No typesetting found for |- ( 1s /su 2s ) = ( { 0s } |s { 1s } ) with typecode |-