Metamath Proof Explorer


Theorem mplvrpmga

Description: The action of permuting variables in a multivariate polynomial is a group action. (Contributed by Thierry Arnoux, 10-Jan-2026)

Ref Expression
Hypotheses mplvrpmga.1 S = SymGrp I
mplvrpmga.2 P = Base S
mplvrpmga.3 M = Base I mPoly R
mplvrpmga.4 A = d P , f M x h 0 I | finSupp 0 h f x d
mplvrpmga.5 φ I V
Assertion mplvrpmga φ A S GrpAct M

Proof

Step Hyp Ref Expression
1 mplvrpmga.1 S = SymGrp I
2 mplvrpmga.2 P = Base S
3 mplvrpmga.3 M = Base I mPoly R
4 mplvrpmga.4 A = d P , f M x h 0 I | finSupp 0 h f x d
5 mplvrpmga.5 φ I V
6 1 symggrp I V S Grp
7 5 6 syl φ S Grp
8 3 fvexi M V
9 8 a1i φ M V
10 fvexd φ c P × M Base R V
11 ovex 0 I V
12 11 rabex h 0 I | finSupp 0 h V
13 12 a1i φ c P × M h 0 I | finSupp 0 h V
14 eqid I mPoly R = I mPoly R
15 eqid Base R = Base R
16 eqid h 0 I | finSupp 0 h = h 0 I | finSupp 0 h
17 16 psrbasfsupp h 0 I | finSupp 0 h = h 0 I | h -1 Fin
18 xp2nd c P × M 2 nd c M
19 18 ad2antlr φ c P × M x h 0 I | finSupp 0 h 2 nd c M
20 14 15 3 17 19 mplelf φ c P × M x h 0 I | finSupp 0 h 2 nd c : h 0 I | finSupp 0 h Base R
21 5 ad2antrr φ c P × M x h 0 I | finSupp 0 h I V
22 xp1st c P × M 1 st c P
23 22 ad2antlr φ c P × M x h 0 I | finSupp 0 h 1 st c P
24 simpr φ c P × M x h 0 I | finSupp 0 h x h 0 I | finSupp 0 h
25 1 2 21 23 24 mplvrpmlem φ c P × M x h 0 I | finSupp 0 h x 1 st c h 0 I | finSupp 0 h
26 20 25 ffvelcdmd φ c P × M x h 0 I | finSupp 0 h 2 nd c x 1 st c Base R
27 26 fmpttd φ c P × M x h 0 I | finSupp 0 h 2 nd c x 1 st c : h 0 I | finSupp 0 h Base R
28 10 13 27 elmapdd φ c P × M x h 0 I | finSupp 0 h 2 nd c x 1 st c Base R h 0 I | finSupp 0 h
29 eqid I mPwSer R = I mPwSer R
30 eqid Base I mPwSer R = Base I mPwSer R
31 29 15 17 30 5 psrbas φ Base I mPwSer R = Base R h 0 I | finSupp 0 h
32 31 adantr φ c P × M Base I mPwSer R = Base R h 0 I | finSupp 0 h
33 28 32 eleqtrrd φ c P × M x h 0 I | finSupp 0 h 2 nd c x 1 st c Base I mPwSer R
34 coeq1 x = y x 1 st c = y 1 st c
35 34 fveq2d x = y 2 nd c x 1 st c = 2 nd c y 1 st c
36 35 cbvmptv x h 0 I | finSupp 0 h 2 nd c x 1 st c = y h 0 I | finSupp 0 h 2 nd c y 1 st c
37 fveq1 g = 2 nd c g y q = 2 nd c y q
38 37 mpteq2dv g = 2 nd c y h 0 I | finSupp 0 h g y q = y h 0 I | finSupp 0 h 2 nd c y q
39 38 breq1d g = 2 nd c finSupp 0 R y h 0 I | finSupp 0 h g y q finSupp 0 R y h 0 I | finSupp 0 h 2 nd c y q
40 coeq2 q = 1 st c y q = y 1 st c
41 40 fveq2d q = 1 st c 2 nd c y q = 2 nd c y 1 st c
42 41 mpteq2dv q = 1 st c y h 0 I | finSupp 0 h 2 nd c y q = y h 0 I | finSupp 0 h 2 nd c y 1 st c
43 42 breq1d q = 1 st c finSupp 0 R y h 0 I | finSupp 0 h 2 nd c y q finSupp 0 R y h 0 I | finSupp 0 h 2 nd c y 1 st c
44 4 a1i φ g M q P A = d P , f M x h 0 I | finSupp 0 h f x d
45 simpr d = q f = g f = g
46 coeq2 d = q x d = x q
47 46 adantr d = q f = g x d = x q
48 45 47 fveq12d d = q f = g f x d = g x q
49 48 mpteq2dv d = q f = g x h 0 I | finSupp 0 h f x d = x h 0 I | finSupp 0 h g x q
50 49 adantl φ g M q P d = q f = g x h 0 I | finSupp 0 h f x d = x h 0 I | finSupp 0 h g x q
51 simpr φ g M q P q P
52 simplr φ g M q P g M
53 12 mptex x h 0 I | finSupp 0 h g x q V
54 53 a1i φ g M q P x h 0 I | finSupp 0 h g x q V
55 44 50 51 52 54 ovmpod φ g M q P q A g = x h 0 I | finSupp 0 h g x q
56 coeq1 x = y x q = y q
57 56 fveq2d x = y g x q = g y q
58 57 cbvmptv x h 0 I | finSupp 0 h g x q = y h 0 I | finSupp 0 h g y q
59 55 58 eqtrdi φ g M q P q A g = y h 0 I | finSupp 0 h g y q
60 5 ad2antrr φ g M q P I V
61 eqid 0 R = 0 R
62 1 2 3 4 60 61 52 51 mplvrpmfgalem φ g M q P finSupp 0 R q A g
63 59 62 eqbrtrrd φ g M q P finSupp 0 R y h 0 I | finSupp 0 h g y q
64 63 anasss φ g M q P finSupp 0 R y h 0 I | finSupp 0 h g y q
65 64 ralrimivva φ g M q P finSupp 0 R y h 0 I | finSupp 0 h g y q
66 65 adantr φ c P × M g M q P finSupp 0 R y h 0 I | finSupp 0 h g y q
67 18 adantl φ c P × M 2 nd c M
68 22 adantl φ c P × M 1 st c P
69 39 43 66 67 68 rspc2dv φ c P × M finSupp 0 R y h 0 I | finSupp 0 h 2 nd c y 1 st c
70 36 69 eqbrtrid φ c P × M finSupp 0 R x h 0 I | finSupp 0 h 2 nd c x 1 st c
71 14 29 30 61 3 mplelbas x h 0 I | finSupp 0 h 2 nd c x 1 st c M x h 0 I | finSupp 0 h 2 nd c x 1 st c Base I mPwSer R finSupp 0 R x h 0 I | finSupp 0 h 2 nd c x 1 st c
72 33 70 71 sylanbrc φ c P × M x h 0 I | finSupp 0 h 2 nd c x 1 st c M
73 vex d V
74 vex f V
75 73 74 op2ndd c = d f 2 nd c = f
76 73 74 op1std c = d f 1 st c = d
77 76 coeq2d c = d f x 1 st c = x d
78 75 77 fveq12d c = d f 2 nd c x 1 st c = f x d
79 78 mpteq2dv c = d f x h 0 I | finSupp 0 h 2 nd c x 1 st c = x h 0 I | finSupp 0 h f x d
80 79 mpompt c P × M x h 0 I | finSupp 0 h 2 nd c x 1 st c = d P , f M x h 0 I | finSupp 0 h f x d
81 4 80 eqtr4i A = c P × M x h 0 I | finSupp 0 h 2 nd c x 1 st c
82 72 81 fmptd φ A : P × M M
83 1 symgid I V I I = 0 S
84 5 83 syl φ I I = 0 S
85 84 adantr φ g M I I = 0 S
86 85 oveq1d φ g M I I A g = 0 S A g
87 4 a1i φ g M A = d P , f M x h 0 I | finSupp 0 h f x d
88 ssrab2 h 0 I | finSupp 0 h 0 I
89 88 a1i φ g M h 0 I | finSupp 0 h 0 I
90 89 sselda φ g M x h 0 I | finSupp 0 h x 0 I
91 90 elmaprd φ g M x h 0 I | finSupp 0 h x : I 0
92 fcoi1 x : I 0 x I I = x
93 91 92 syl φ g M x h 0 I | finSupp 0 h x I I = x
94 93 fveq2d φ g M x h 0 I | finSupp 0 h g x I I = g x
95 94 mpteq2dva φ g M x h 0 I | finSupp 0 h g x I I = x h 0 I | finSupp 0 h g x
96 95 adantr φ g M d = I I f = g x h 0 I | finSupp 0 h g x I I = x h 0 I | finSupp 0 h g x
97 simpr d = I I f = g f = g
98 coeq2 d = I I x d = x I I
99 98 adantr d = I I f = g x d = x I I
100 97 99 fveq12d d = I I f = g f x d = g x I I
101 100 mpteq2dv d = I I f = g x h 0 I | finSupp 0 h f x d = x h 0 I | finSupp 0 h g x I I
102 101 adantl φ g M d = I I f = g x h 0 I | finSupp 0 h f x d = x h 0 I | finSupp 0 h g x I I
103 14 29 30 61 3 mplelbas g M g Base I mPwSer R finSupp 0 R g
104 103 simplbi g M g Base I mPwSer R
105 29 15 17 30 104 psrelbas g M g : h 0 I | finSupp 0 h Base R
106 105 ad3antlr φ g M d = I I f = g g : h 0 I | finSupp 0 h Base R
107 106 feqmptd φ g M d = I I f = g g = x h 0 I | finSupp 0 h g x
108 107 anasss φ g M d = I I f = g g = x h 0 I | finSupp 0 h g x
109 96 102 108 3eqtr4d φ g M d = I I f = g x h 0 I | finSupp 0 h f x d = g
110 eqid 0 S = 0 S
111 2 110 grpidcl S Grp 0 S P
112 5 6 111 3syl φ 0 S P
113 84 112 eqeltrd φ I I P
114 113 adantr φ g M I I P
115 simpr φ g M g M
116 87 109 114 115 115 ovmpod φ g M I I A g = g
117 86 116 eqtr3d φ g M 0 S A g = g
118 eqid + S = + S
119 1 2 118 symgov p P q P p + S q = p q
120 119 adantll φ g M p P q P p + S q = p q
121 120 oveq1d φ g M p P q P p + S q A g = p q A g
122 coass x p q = x p q
123 122 a1i φ g M p P q P x h 0 I | finSupp 0 h x p q = x p q
124 123 fveq2d φ g M p P q P x h 0 I | finSupp 0 h g x p q = g x p q
125 124 mpteq2dva φ g M p P q P x h 0 I | finSupp 0 h g x p q = x h 0 I | finSupp 0 h g x p q
126 59 adantlr φ g M p P q P q A g = y h 0 I | finSupp 0 h g y q
127 126 oveq2d φ g M p P q P p A q A g = p A y h 0 I | finSupp 0 h g y q
128 4 a1i φ g M p P q P A = d P , f M x h 0 I | finSupp 0 h f x d
129 simpllr φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h d = p
130 129 coeq2d φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h x d = x p
131 130 fveq2d φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h f x d = f x p
132 simplr φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h f = y h 0 I | finSupp 0 h g y q
133 simpr φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h y = x p y = x p
134 133 coeq1d φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h y = x p y q = x p q
135 134 fveq2d φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h y = x p g y q = g x p q
136 breq1 h = x p finSupp 0 h finSupp 0 x p
137 nn0ex 0 V
138 137 a1i φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h 0 V
139 5 ad3antrrr φ g M p P q P I V
140 139 ad3antrrr φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h I V
141 88 a1i φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q h 0 I | finSupp 0 h 0 I
142 141 sselda φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h x 0 I
143 142 elmaprd φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h x : I 0
144 1 2 symgbasf p P p : I I
145 144 ad5antlr φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h p : I I
146 143 145 fcod φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h x p : I 0
147 138 140 146 elmapdd φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h x p 0 I
148 breq1 h = x finSupp 0 h finSupp 0 x
149 148 elrab x h 0 I | finSupp 0 h x 0 I finSupp 0 x
150 149 simprbi x h 0 I | finSupp 0 h finSupp 0 x
151 150 adantl φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h finSupp 0 x
152 1 2 symgbasf1o p P p : I 1-1 onto I
153 f1of1 p : I 1-1 onto I p : I 1-1 I
154 152 153 syl p P p : I 1-1 I
155 154 ad5antlr φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h p : I 1-1 I
156 0nn0 0 0
157 156 a1i φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h 0 0
158 simpr φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h x h 0 I | finSupp 0 h
159 151 155 157 158 fsuppco φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h finSupp 0 x p
160 136 147 159 elrabd φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h x p h 0 I | finSupp 0 h
161 fvexd φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h g x p q V
162 nfv y φ g M p P q P d = p
163 nfmpt1 _ y y h 0 I | finSupp 0 h g y q
164 163 nfeq2 y f = y h 0 I | finSupp 0 h g y q
165 162 164 nfan y φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q
166 nfv y x h 0 I | finSupp 0 h
167 165 166 nfan y φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h
168 nfcv _ y x p
169 nfcv _ y g x p q
170 132 135 160 161 167 168 169 fvmptdf φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h f x p = g x p q
171 131 170 eqtrd φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h f x d = g x p q
172 171 mpteq2dva φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h f x d = x h 0 I | finSupp 0 h g x p q
173 172 anasss φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q x h 0 I | finSupp 0 h f x d = x h 0 I | finSupp 0 h g x p q
174 simplr φ g M p P q P p P
175 fvexd φ g M p P q P Base R V
176 12 a1i φ g M p P q P h 0 I | finSupp 0 h V
177 115 ad3antrrr φ g M p P q P y h 0 I | finSupp 0 h g M
178 14 15 3 17 177 mplelf φ g M p P q P y h 0 I | finSupp 0 h g : h 0 I | finSupp 0 h Base R
179 breq1 h = y q finSupp 0 h finSupp 0 y q
180 137 a1i φ g M p P q P y h 0 I | finSupp 0 h 0 V
181 139 adantr φ g M p P q P y h 0 I | finSupp 0 h I V
182 88 a1i φ g M p P q P h 0 I | finSupp 0 h 0 I
183 182 sselda φ g M p P q P y h 0 I | finSupp 0 h y 0 I
184 183 elmaprd φ g M p P q P y h 0 I | finSupp 0 h y : I 0
185 1 2 symgbasf q P q : I I
186 185 ad2antlr φ g M p P q P y h 0 I | finSupp 0 h q : I I
187 184 186 fcod φ g M p P q P y h 0 I | finSupp 0 h y q : I 0
188 180 181 187 elmapdd φ g M p P q P y h 0 I | finSupp 0 h y q 0 I
189 breq1 h = y finSupp 0 h finSupp 0 y
190 189 elrab y h 0 I | finSupp 0 h y 0 I finSupp 0 y
191 190 simprbi y h 0 I | finSupp 0 h finSupp 0 y
192 191 adantl φ g M p P q P y h 0 I | finSupp 0 h finSupp 0 y
193 1 2 symgbasf1o q P q : I 1-1 onto I
194 193 ad2antlr φ g M p P q P y h 0 I | finSupp 0 h q : I 1-1 onto I
195 f1of1 q : I 1-1 onto I q : I 1-1 I
196 194 195 syl φ g M p P q P y h 0 I | finSupp 0 h q : I 1-1 I
197 156 a1i φ g M p P q P y h 0 I | finSupp 0 h 0 0
198 simpr φ g M p P q P y h 0 I | finSupp 0 h y h 0 I | finSupp 0 h
199 192 196 197 198 fsuppco φ g M p P q P y h 0 I | finSupp 0 h finSupp 0 y q
200 179 188 199 elrabd φ g M p P q P y h 0 I | finSupp 0 h y q h 0 I | finSupp 0 h
201 178 200 ffvelcdmd φ g M p P q P y h 0 I | finSupp 0 h g y q Base R
202 201 fmpttd φ g M p P q P y h 0 I | finSupp 0 h g y q : h 0 I | finSupp 0 h Base R
203 175 176 202 elmapdd φ g M p P q P y h 0 I | finSupp 0 h g y q Base R h 0 I | finSupp 0 h
204 31 ad3antrrr φ g M p P q P Base I mPwSer R = Base R h 0 I | finSupp 0 h
205 203 204 eleqtrrd φ g M p P q P y h 0 I | finSupp 0 h g y q Base I mPwSer R
206 63 adantlr φ g M p P q P finSupp 0 R y h 0 I | finSupp 0 h g y q
207 14 29 30 61 3 mplelbas y h 0 I | finSupp 0 h g y q M y h 0 I | finSupp 0 h g y q Base I mPwSer R finSupp 0 R y h 0 I | finSupp 0 h g y q
208 205 206 207 sylanbrc φ g M p P q P y h 0 I | finSupp 0 h g y q M
209 176 mptexd φ g M p P q P x h 0 I | finSupp 0 h g x p q V
210 128 173 174 208 209 ovmpod φ g M p P q P p A y h 0 I | finSupp 0 h g y q = x h 0 I | finSupp 0 h g x p q
211 127 210 eqtrd φ g M p P q P p A q A g = x h 0 I | finSupp 0 h g x p q
212 simpr d = p q f = g f = g
213 coeq2 d = p q x d = x p q
214 213 adantr d = p q f = g x d = x p q
215 212 214 fveq12d d = p q f = g f x d = g x p q
216 215 mpteq2dv d = p q f = g x h 0 I | finSupp 0 h f x d = x h 0 I | finSupp 0 h g x p q
217 216 adantl φ g M p P q P d = p q f = g x h 0 I | finSupp 0 h f x d = x h 0 I | finSupp 0 h g x p q
218 139 6 syl φ g M p P q P S Grp
219 simpr φ g M p P q P q P
220 2 118 218 174 219 grpcld φ g M p P q P p + S q P
221 120 220 eqeltrrd φ g M p P q P p q P
222 simpllr φ g M p P q P g M
223 176 mptexd φ g M p P q P x h 0 I | finSupp 0 h g x p q V
224 128 217 221 222 223 ovmpod φ g M p P q P p q A g = x h 0 I | finSupp 0 h g x p q
225 125 211 224 3eqtr4rd φ g M p P q P p q A g = p A q A g
226 121 225 eqtrd φ g M p P q P p + S q A g = p A q A g
227 226 anasss φ g M p P q P p + S q A g = p A q A g
228 227 ralrimivva φ g M p P q P p + S q A g = p A q A g
229 117 228 jca φ g M 0 S A g = g p P q P p + S q A g = p A q A g
230 229 ralrimiva φ g M 0 S A g = g p P q P p + S q A g = p A q A g
231 2 118 110 isga A S GrpAct M S Grp M V A : P × M M g M 0 S A g = g p P q P p + S q A g = p A q A g
232 7 9 82 230 231 syl22anbrc φ A S GrpAct M