Metamath Proof Explorer


Theorem constrextdg2lem

Description: Lemma for constrextdg2 (Contributed by Thierry Arnoux, 19-Oct-2025)

Ref Expression
Hypotheses constr0.1 C = rec s V x | a s b s c s d s t r x = a + t b a x = c + r d c b a d c 0 a s b s c s e s f s t x = a + t b a x c = e f a s b s c s d s e s f s a d x a = b c x d = e f 0 1
constrextdg2.1 E = fld 𝑠 e
constrextdg2.2 F = fld 𝑠 f
constrextdg2.l < ˙ = f e | E /FldExt F E .:. F = 2
constrextdg2.n φ N ω
constrextdg2lem.1 φ R Chain SubDRing fld < ˙
constrextdg2lem.2 φ R 0 =
constrextdg2lem.3 φ C N lastS R
Assertion constrextdg2lem φ v Chain SubDRing fld < ˙ v 0 = C suc N lastS v

Proof

Step Hyp Ref Expression
1 constr0.1 C = rec s V x | a s b s c s d s t r x = a + t b a x = c + r d c b a d c 0 a s b s c s e s f s t x = a + t b a x c = e f a s b s c s d s e s f s a d x a = b c x d = e f 0 1
2 constrextdg2.1 E = fld 𝑠 e
3 constrextdg2.2 F = fld 𝑠 f
4 constrextdg2.l < ˙ = f e | E /FldExt F E .:. F = 2
5 constrextdg2.n φ N ω
6 constrextdg2lem.1 φ R Chain SubDRing fld < ˙
7 constrextdg2lem.2 φ R 0 =
8 constrextdg2lem.3 φ C N lastS R
9 uneq2 i = C N i = C N
10 9 sseq1d i = C N i lastS v C N lastS v
11 10 anbi2d i = v 0 = C N i lastS v v 0 = C N lastS v
12 11 rexbidv i = v Chain SubDRing fld < ˙ v 0 = C N i lastS v v Chain SubDRing fld < ˙ v 0 = C N lastS v
13 uneq2 i = g C N i = C N g
14 13 sseq1d i = g C N i lastS v C N g lastS v
15 14 anbi2d i = g v 0 = C N i lastS v v 0 = C N g lastS v
16 15 rexbidv i = g v Chain SubDRing fld < ˙ v 0 = C N i lastS v v Chain SubDRing fld < ˙ v 0 = C N g lastS v
17 fveq1 v = u v 0 = u 0
18 17 eqeq1d v = u v 0 = u 0 =
19 fveq2 v = u lastS v = lastS u
20 19 sseq2d v = u C N i lastS v C N i lastS u
21 18 20 anbi12d v = u v 0 = C N i lastS v u 0 = C N i lastS u
22 21 cbvrexvw v Chain SubDRing fld < ˙ v 0 = C N i lastS v u Chain SubDRing fld < ˙ u 0 = C N i lastS u
23 uneq2 i = g y C N i = C N g y
24 23 sseq1d i = g y C N i lastS u C N g y lastS u
25 24 anbi2d i = g y u 0 = C N i lastS u u 0 = C N g y lastS u
26 25 rexbidv i = g y u Chain SubDRing fld < ˙ u 0 = C N i lastS u u Chain SubDRing fld < ˙ u 0 = C N g y lastS u
27 22 26 bitrid i = g y v Chain SubDRing fld < ˙ v 0 = C N i lastS v u Chain SubDRing fld < ˙ u 0 = C N g y lastS u
28 uneq2 i = C suc N C N i = C N C suc N
29 28 sseq1d i = C suc N C N i lastS v C N C suc N lastS v
30 29 anbi2d i = C suc N v 0 = C N i lastS v v 0 = C N C suc N lastS v
31 30 rexbidv i = C suc N v Chain SubDRing fld < ˙ v 0 = C N i lastS v v Chain SubDRing fld < ˙ v 0 = C N C suc N lastS v
32 fveq1 v = R v 0 = R 0
33 32 eqeq1d v = R v 0 = R 0 =
34 fveq2 v = R lastS v = lastS R
35 34 sseq2d v = R C N lastS v C N lastS R
36 33 35 anbi12d v = R v 0 = C N lastS v R 0 = C N lastS R
37 un0 C N = C N
38 37 8 eqsstrid φ C N lastS R
39 7 38 jca φ R 0 = C N lastS R
40 36 6 39 rspcedvdw φ v Chain SubDRing fld < ˙ v 0 = C N lastS v
41 fveq1 u = v u 0 = v 0
42 41 eqeq1d u = v u 0 = v 0 =
43 fveq2 u = v lastS u = lastS v
44 43 sseq2d u = v C N g y lastS u C N g y lastS v
45 42 44 anbi12d u = v u 0 = C N g y lastS u v 0 = C N g y lastS v
46 simpllr φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v v Chain SubDRing fld < ˙
47 46 adantr φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v y lastS v v Chain SubDRing fld < ˙
48 simpllr φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v y lastS v v 0 =
49 simpr φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v C N g lastS v
50 49 unssad φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v C N lastS v
51 50 adantr φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v y lastS v C N lastS v
52 simplr φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v y lastS v C N g lastS v
53 52 unssbd φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v y lastS v g lastS v
54 simpr φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v y lastS v y lastS v
55 54 snssd φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v y lastS v y lastS v
56 53 55 unssd φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v y lastS v g y lastS v
57 51 56 unssd φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v y lastS v C N g y lastS v
58 48 57 jca φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v y lastS v v 0 = C N g y lastS v
59 45 47 58 rspcedvdw φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v y lastS v u Chain SubDRing fld < ˙ u 0 = C N g y lastS u
60 fveq1 u = v ++ ⟨“ fld fldGen lastS v y ”⟩ u 0 = v ++ ⟨“ fld fldGen lastS v y ”⟩ 0
61 60 eqeq1d u = v ++ ⟨“ fld fldGen lastS v y ”⟩ u 0 = v ++ ⟨“ fld fldGen lastS v y ”⟩ 0 =
62 fveq2 u = v ++ ⟨“ fld fldGen lastS v y ”⟩ lastS u = lastS v ++ ⟨“ fld fldGen lastS v y ”⟩
63 62 sseq2d u = v ++ ⟨“ fld fldGen lastS v y ”⟩ C N g y lastS u C N g y lastS v ++ ⟨“ fld fldGen lastS v y ”⟩
64 61 63 anbi12d u = v ++ ⟨“ fld fldGen lastS v y ”⟩ u 0 = C N g y lastS u v ++ ⟨“ fld fldGen lastS v y ”⟩ 0 = C N g y lastS v ++ ⟨“ fld fldGen lastS v y ”⟩
65 cnfldbas = Base fld
66 cndrng fld DivRing
67 66 a1i φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 fld DivRing
68 46 chnwrd φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v v Word SubDRing fld
69 simpr φ C N g lastS v v = v =
70 69 fveq2d φ C N g lastS v v = lastS v = lastS
71 lsw0g lastS =
72 70 71 eqtrdi φ C N g lastS v v = lastS v =
73 simplr φ C N g lastS v v = C N g lastS v
74 ssun1 C N C N g
75 nnon N ω N On
76 5 75 syl φ N On
77 1 76 constr01 φ 0 1 C N
78 c0ex 0 V
79 78 prnz 0 1
80 ssn0 0 1 C N 0 1 C N
81 77 79 80 sylancl φ C N
82 ssn0 C N C N g C N C N g
83 74 81 82 sylancr φ C N g
84 83 ad2antrr φ C N g lastS v v = C N g
85 ssn0 C N g lastS v C N g lastS v
86 73 84 85 syl2anc φ C N g lastS v v = lastS v
87 86 neneqd φ C N g lastS v v = ¬ lastS v =
88 72 87 pm2.65da φ C N g lastS v ¬ v =
89 88 neqned φ C N g lastS v v
90 89 ad4antr φ C N g lastS v y C suc N g v Chain SubDRing fld < ˙ v 0 = g C suc N v
91 90 an62ds φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v v
92 lswcl v Word SubDRing fld v lastS v SubDRing fld
93 68 91 92 syl2anc φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v lastS v SubDRing fld
94 93 adantr φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 lastS v SubDRing fld
95 65 sdrgss lastS v SubDRing fld lastS v
96 94 95 syl φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 lastS v
97 onsuc N On suc N On
98 76 97 syl φ suc N On
99 1 98 constrsscn φ C suc N
100 99 ad6antr φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 C suc N
101 simp-4r φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v y C suc N g
102 101 eldifad φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v y C suc N
103 102 adantr φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 y C suc N
104 100 103 sseldd φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 y
105 104 snssd φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 y
106 96 105 unssd φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 lastS v y
107 65 67 106 fldgensdrg φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 fld fldGen lastS v y SubDRing fld
108 46 adantr φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 v Chain SubDRing fld < ˙
109 94 elexd φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 lastS v V
110 107 elexd φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 fld fldGen lastS v y V
111 eqid fld 𝑠 lastS v = fld 𝑠 lastS v
112 eqid fld 𝑠 fld fldGen lastS v y = fld 𝑠 fld fldGen lastS v y
113 cnfldfld fld Field
114 113 a1i φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 fld Field
115 65 111 112 114 94 105 fldgenfldext φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 fld 𝑠 fld fldGen lastS v y /FldExt fld 𝑠 lastS v
116 simpr φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2
117 2 3 breq12i E /FldExt F fld 𝑠 e /FldExt fld 𝑠 f
118 oveq2 e = fld fldGen lastS v y fld 𝑠 e = fld 𝑠 fld fldGen lastS v y
119 118 adantl f = lastS v e = fld fldGen lastS v y fld 𝑠 e = fld 𝑠 fld fldGen lastS v y
120 oveq2 f = lastS v fld 𝑠 f = fld 𝑠 lastS v
121 120 adantr f = lastS v e = fld fldGen lastS v y fld 𝑠 f = fld 𝑠 lastS v
122 119 121 breq12d f = lastS v e = fld fldGen lastS v y fld 𝑠 e /FldExt fld 𝑠 f fld 𝑠 fld fldGen lastS v y /FldExt fld 𝑠 lastS v
123 117 122 bitrid f = lastS v e = fld fldGen lastS v y E /FldExt F fld 𝑠 fld fldGen lastS v y /FldExt fld 𝑠 lastS v
124 2 3 oveq12i E .:. F = fld 𝑠 e .:. fld 𝑠 f
125 119 121 oveq12d f = lastS v e = fld fldGen lastS v y fld 𝑠 e .:. fld 𝑠 f = fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v
126 124 125 eqtrid f = lastS v e = fld fldGen lastS v y E .:. F = fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v
127 126 eqeq1d f = lastS v e = fld fldGen lastS v y E .:. F = 2 fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2
128 123 127 anbi12d f = lastS v e = fld fldGen lastS v y E /FldExt F E .:. F = 2 fld 𝑠 fld fldGen lastS v y /FldExt fld 𝑠 lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2
129 128 4 brabga lastS v V fld fldGen lastS v y V lastS v < ˙ fld fldGen lastS v y fld 𝑠 fld fldGen lastS v y /FldExt fld 𝑠 lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2
130 129 biimpar lastS v V fld fldGen lastS v y V fld 𝑠 fld fldGen lastS v y /FldExt fld 𝑠 lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 lastS v < ˙ fld fldGen lastS v y
131 109 110 115 116 130 syl22anc φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 lastS v < ˙ fld fldGen lastS v y
132 131 olcd φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 v = lastS v < ˙ fld fldGen lastS v y
133 107 108 132 chnccats1 φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 v ++ ⟨“ fld fldGen lastS v y ”⟩ Chain SubDRing fld < ˙
134 68 adantr φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 v Word SubDRing fld
135 107 s1cld φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 ⟨“ fld fldGen lastS v y ”⟩ Word SubDRing fld
136 hashgt0 v Chain SubDRing fld < ˙ v 0 < v
137 46 91 136 syl2anc φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v 0 < v
138 137 adantr φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 0 < v
139 ccatfv0 v Word SubDRing fld ⟨“ fld fldGen lastS v y ”⟩ Word SubDRing fld 0 < v v ++ ⟨“ fld fldGen lastS v y ”⟩ 0 = v 0
140 134 135 138 139 syl3anc φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 v ++ ⟨“ fld fldGen lastS v y ”⟩ 0 = v 0
141 simpllr φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 v 0 =
142 140 141 eqtrd φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 v ++ ⟨“ fld fldGen lastS v y ”⟩ 0 =
143 50 adantr φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 C N lastS v
144 ssun3 C N lastS v C N lastS v y
145 143 144 syl φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 C N lastS v y
146 simplr φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 C N g lastS v
147 146 unssbd φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 g lastS v
148 ssun3 g lastS v g lastS v y
149 147 148 syl φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 g lastS v y
150 ssun2 y lastS v y
151 150 a1i φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 y lastS v y
152 149 151 unssd φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 g y lastS v y
153 145 152 unssd φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 C N g y lastS v y
154 65 67 106 fldgenssid φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 lastS v y fld fldGen lastS v y
155 153 154 sstrd φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 C N g y fld fldGen lastS v y
156 lswccats1 v Word SubDRing fld fld fldGen lastS v y SubDRing fld lastS v ++ ⟨“ fld fldGen lastS v y ”⟩ = fld fldGen lastS v y
157 134 107 156 syl2anc φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 lastS v ++ ⟨“ fld fldGen lastS v y ”⟩ = fld fldGen lastS v y
158 155 157 sseqtrrd φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 C N g y lastS v ++ ⟨“ fld fldGen lastS v y ”⟩
159 142 158 jca φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 v ++ ⟨“ fld fldGen lastS v y ”⟩ 0 = C N g y lastS v ++ ⟨“ fld fldGen lastS v y ”⟩
160 64 133 159 rspcedvdw φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2 u Chain SubDRing fld < ˙ u 0 = C N g y lastS u
161 76 ad5antr φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v N On
162 1 111 112 93 161 50 102 constrelextdg2 φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v y lastS v fld 𝑠 fld fldGen lastS v y .:. fld 𝑠 lastS v = 2
163 59 160 162 mpjaodan φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v u Chain SubDRing fld < ˙ u 0 = C N g y lastS u
164 163 anasss φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v u Chain SubDRing fld < ˙ u 0 = C N g y lastS u
165 164 rexlimdva2 φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v u Chain SubDRing fld < ˙ u 0 = C N g y lastS u
166 165 anasss φ g C suc N y C suc N g v Chain SubDRing fld < ˙ v 0 = C N g lastS v u Chain SubDRing fld < ˙ u 0 = C N g y lastS u
167 peano2 N ω suc N ω
168 5 167 syl φ suc N ω
169 1 168 constrfin φ C suc N Fin
170 12 16 27 31 40 166 169 findcard2d φ v Chain SubDRing fld < ˙ v 0 = C N C suc N lastS v
171 simpr φ v Chain SubDRing fld < ˙ C N C suc N lastS v C N C suc N lastS v
172 171 unssbd φ v Chain SubDRing fld < ˙ C N C suc N lastS v C suc N lastS v
173 172 ex φ v Chain SubDRing fld < ˙ C N C suc N lastS v C suc N lastS v
174 173 anim2d φ v Chain SubDRing fld < ˙ v 0 = C N C suc N lastS v v 0 = C suc N lastS v
175 174 reximdva φ v Chain SubDRing fld < ˙ v 0 = C N C suc N lastS v v Chain SubDRing fld < ˙ v 0 = C suc N lastS v
176 170 175 mpd φ v Chain SubDRing fld < ˙ v 0 = C suc N lastS v