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 breq1 h = x 1 st c finSupp 0 h finSupp 0 x 1 st c
22 nn0ex 0 V
23 22 a1i φ c P × M x h 0 I | finSupp 0 h 0 V
24 5 ad2antrr φ c P × M x h 0 I | finSupp 0 h I V
25 ssrab2 h 0 I | finSupp 0 h 0 I
26 25 a1i φ c P × M h 0 I | finSupp 0 h 0 I
27 26 sselda φ c P × M x h 0 I | finSupp 0 h x 0 I
28 24 23 27 elmaprd φ c P × M x h 0 I | finSupp 0 h x : I 0
29 xp1st c P × M 1 st c P
30 29 ad2antlr φ c P × M x h 0 I | finSupp 0 h 1 st c P
31 1 2 symgbasf 1 st c P 1 st c : I I
32 30 31 syl φ c P × M x h 0 I | finSupp 0 h 1 st c : I I
33 28 32 fcod φ c P × M x h 0 I | finSupp 0 h x 1 st c : I 0
34 23 24 33 elmapdd φ c P × M x h 0 I | finSupp 0 h x 1 st c 0 I
35 simpr φ c P × M x h 0 I | finSupp 0 h x h 0 I | finSupp 0 h
36 breq1 h = x finSupp 0 h finSupp 0 x
37 36 elrab x h 0 I | finSupp 0 h x 0 I finSupp 0 x
38 35 37 sylib φ c P × M x h 0 I | finSupp 0 h x 0 I finSupp 0 x
39 38 simprd φ c P × M x h 0 I | finSupp 0 h finSupp 0 x
40 1 2 symgbasf1o 1 st c P 1 st c : I 1-1 onto I
41 f1of1 1 st c : I 1-1 onto I 1 st c : I 1-1 I
42 30 40 41 3syl φ c P × M x h 0 I | finSupp 0 h 1 st c : I 1-1 I
43 0nn0 0 0
44 43 a1i φ c P × M x h 0 I | finSupp 0 h 0 0
45 39 42 44 35 fsuppco φ c P × M x h 0 I | finSupp 0 h finSupp 0 x 1 st c
46 21 34 45 elrabd φ c P × M x h 0 I | finSupp 0 h x 1 st c h 0 I | finSupp 0 h
47 20 46 ffvelcdmd φ c P × M x h 0 I | finSupp 0 h 2 nd c x 1 st c Base R
48 47 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
49 10 13 48 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
50 eqid I mPwSer R = I mPwSer R
51 eqid Base I mPwSer R = Base I mPwSer R
52 50 15 17 51 5 psrbas φ Base I mPwSer R = Base R h 0 I | finSupp 0 h
53 52 adantr φ c P × M Base I mPwSer R = Base R h 0 I | finSupp 0 h
54 49 53 eleqtrrd φ c P × M x h 0 I | finSupp 0 h 2 nd c x 1 st c Base I mPwSer R
55 coeq1 x = y x 1 st c = y 1 st c
56 55 fveq2d x = y 2 nd c x 1 st c = 2 nd c y 1 st c
57 56 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
58 fveq1 g = 2 nd c g y q = 2 nd c y q
59 58 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
60 59 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
61 coeq2 q = 1 st c y q = y 1 st c
62 61 fveq2d q = 1 st c 2 nd c y q = 2 nd c y 1 st c
63 62 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
64 63 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
65 4 a1i φ g M q P A = d P , f M x h 0 I | finSupp 0 h f x d
66 simpr d = q f = g f = g
67 coeq2 d = q x d = x q
68 67 adantr d = q f = g x d = x q
69 66 68 fveq12d d = q f = g f x d = g x q
70 69 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
71 70 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
72 simpr φ g M q P q P
73 simplr φ g M q P g M
74 12 mptex x h 0 I | finSupp 0 h g x q V
75 74 a1i φ g M q P x h 0 I | finSupp 0 h g x q V
76 65 71 72 73 75 ovmpod φ g M q P q A g = x h 0 I | finSupp 0 h g x q
77 coeq1 x = y x q = y q
78 77 fveq2d x = y g x q = g y q
79 78 cbvmptv x h 0 I | finSupp 0 h g x q = y h 0 I | finSupp 0 h g y q
80 76 79 eqtrdi φ g M q P q A g = y h 0 I | finSupp 0 h g y q
81 5 ad2antrr φ g M q P I V
82 eqid 0 R = 0 R
83 1 2 3 4 81 82 73 72 mplvrpmfgalem φ g M q P finSupp 0 R q A g
84 80 83 eqbrtrrd φ g M q P finSupp 0 R y h 0 I | finSupp 0 h g y q
85 84 anasss φ g M q P finSupp 0 R y h 0 I | finSupp 0 h g y q
86 85 ralrimivva φ g M q P finSupp 0 R y h 0 I | finSupp 0 h g y q
87 86 adantr φ c P × M g M q P finSupp 0 R y h 0 I | finSupp 0 h g y q
88 18 adantl φ c P × M 2 nd c M
89 29 adantl φ c P × M 1 st c P
90 60 64 87 88 89 rspc2dv φ c P × M finSupp 0 R y h 0 I | finSupp 0 h 2 nd c y 1 st c
91 57 90 eqbrtrid φ c P × M finSupp 0 R x h 0 I | finSupp 0 h 2 nd c x 1 st c
92 14 50 51 82 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
93 54 91 92 sylanbrc φ c P × M x h 0 I | finSupp 0 h 2 nd c x 1 st c M
94 vex d V
95 vex f V
96 94 95 op2ndd c = d f 2 nd c = f
97 94 95 op1std c = d f 1 st c = d
98 97 coeq2d c = d f x 1 st c = x d
99 96 98 fveq12d c = d f 2 nd c x 1 st c = f x d
100 99 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
101 100 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
102 4 101 eqtr4i A = c P × M x h 0 I | finSupp 0 h 2 nd c x 1 st c
103 93 102 fmptd φ A : P × M M
104 1 symgid I V I I = 0 S
105 5 104 syl φ I I = 0 S
106 105 adantr φ g M I I = 0 S
107 106 oveq1d φ g M I I A g = 0 S A g
108 4 a1i φ g M A = d P , f M x h 0 I | finSupp 0 h f x d
109 5 ad2antrr φ g M x h 0 I | finSupp 0 h I V
110 22 a1i φ g M x h 0 I | finSupp 0 h 0 V
111 25 a1i φ g M h 0 I | finSupp 0 h 0 I
112 111 sselda φ g M x h 0 I | finSupp 0 h x 0 I
113 109 110 112 elmaprd φ g M x h 0 I | finSupp 0 h x : I 0
114 fcoi1 x : I 0 x I I = x
115 113 114 syl φ g M x h 0 I | finSupp 0 h x I I = x
116 115 fveq2d φ g M x h 0 I | finSupp 0 h g x I I = g x
117 116 mpteq2dva φ g M x h 0 I | finSupp 0 h g x I I = x h 0 I | finSupp 0 h g x
118 117 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
119 simpr d = I I f = g f = g
120 coeq2 d = I I x d = x I I
121 120 adantr d = I I f = g x d = x I I
122 119 121 fveq12d d = I I f = g f x d = g x I I
123 122 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
124 123 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
125 14 50 51 82 3 mplelbas g M g Base I mPwSer R finSupp 0 R g
126 125 simplbi g M g Base I mPwSer R
127 50 15 17 51 126 psrelbas g M g : h 0 I | finSupp 0 h Base R
128 127 ad3antlr φ g M d = I I f = g g : h 0 I | finSupp 0 h Base R
129 128 feqmptd φ g M d = I I f = g g = x h 0 I | finSupp 0 h g x
130 129 anasss φ g M d = I I f = g g = x h 0 I | finSupp 0 h g x
131 118 124 130 3eqtr4d φ g M d = I I f = g x h 0 I | finSupp 0 h f x d = g
132 eqid 0 S = 0 S
133 2 132 grpidcl S Grp 0 S P
134 5 6 133 3syl φ 0 S P
135 105 134 eqeltrd φ I I P
136 135 adantr φ g M I I P
137 simpr φ g M g M
138 108 131 136 137 137 ovmpod φ g M I I A g = g
139 107 138 eqtr3d φ g M 0 S A g = g
140 eqid + S = + S
141 1 2 140 symgov p P q P p + S q = p q
142 141 adantll φ g M p P q P p + S q = p q
143 142 oveq1d φ g M p P q P p + S q A g = p q A g
144 coass x p q = x p q
145 144 a1i φ g M p P q P x h 0 I | finSupp 0 h x p q = x p q
146 145 fveq2d φ g M p P q P x h 0 I | finSupp 0 h g x p q = g x p q
147 146 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
148 80 adantlr φ g M p P q P q A g = y h 0 I | finSupp 0 h g y q
149 148 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
150 4 a1i φ g M p P q P A = d P , f M x h 0 I | finSupp 0 h f x d
151 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
152 151 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
153 152 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
154 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
155 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
156 155 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
157 156 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
158 breq1 h = x p finSupp 0 h finSupp 0 x p
159 22 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
160 5 ad3antrrr φ g M p P q P I V
161 160 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
162 25 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
163 162 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
164 161 159 163 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
165 1 2 symgbasf p P p : I I
166 165 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
167 164 166 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
168 159 161 167 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
169 37 simprbi x h 0 I | finSupp 0 h finSupp 0 x
170 169 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
171 1 2 symgbasf1o p P p : I 1-1 onto I
172 f1of1 p : I 1-1 onto I p : I 1-1 I
173 171 172 syl p P p : I 1-1 I
174 173 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
175 43 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
176 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
177 170 174 175 176 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
178 158 168 177 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
179 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
180 nfv y φ g M p P q P d = p
181 nfmpt1 _ y y h 0 I | finSupp 0 h g y q
182 181 nfeq2 y f = y h 0 I | finSupp 0 h g y q
183 180 182 nfan y φ g M p P q P d = p f = y h 0 I | finSupp 0 h g y q
184 nfv y x h 0 I | finSupp 0 h
185 183 184 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
186 nfcv _ y x p
187 nfcv _ y g x p q
188 154 157 178 179 185 186 187 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
189 153 188 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
190 189 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
191 190 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
192 simplr φ g M p P q P p P
193 fvexd φ g M p P q P Base R V
194 12 a1i φ g M p P q P h 0 I | finSupp 0 h V
195 137 ad3antrrr φ g M p P q P y h 0 I | finSupp 0 h g M
196 14 15 3 17 195 mplelf φ g M p P q P y h 0 I | finSupp 0 h g : h 0 I | finSupp 0 h Base R
197 breq1 h = y q finSupp 0 h finSupp 0 y q
198 22 a1i φ g M p P q P y h 0 I | finSupp 0 h 0 V
199 160 adantr φ g M p P q P y h 0 I | finSupp 0 h I V
200 25 a1i φ g M p P q P h 0 I | finSupp 0 h 0 I
201 200 sselda φ g M p P q P y h 0 I | finSupp 0 h y 0 I
202 199 198 201 elmaprd φ g M p P q P y h 0 I | finSupp 0 h y : I 0
203 1 2 symgbasf q P q : I I
204 203 ad2antlr φ g M p P q P y h 0 I | finSupp 0 h q : I I
205 202 204 fcod φ g M p P q P y h 0 I | finSupp 0 h y q : I 0
206 198 199 205 elmapdd φ g M p P q P y h 0 I | finSupp 0 h y q 0 I
207 breq1 h = y finSupp 0 h finSupp 0 y
208 207 elrab y h 0 I | finSupp 0 h y 0 I finSupp 0 y
209 208 simprbi y h 0 I | finSupp 0 h finSupp 0 y
210 209 adantl φ g M p P q P y h 0 I | finSupp 0 h finSupp 0 y
211 1 2 symgbasf1o q P q : I 1-1 onto I
212 211 ad2antlr φ g M p P q P y h 0 I | finSupp 0 h q : I 1-1 onto I
213 f1of1 q : I 1-1 onto I q : I 1-1 I
214 212 213 syl φ g M p P q P y h 0 I | finSupp 0 h q : I 1-1 I
215 43 a1i φ g M p P q P y h 0 I | finSupp 0 h 0 0
216 simpr φ g M p P q P y h 0 I | finSupp 0 h y h 0 I | finSupp 0 h
217 210 214 215 216 fsuppco φ g M p P q P y h 0 I | finSupp 0 h finSupp 0 y q
218 197 206 217 elrabd φ g M p P q P y h 0 I | finSupp 0 h y q h 0 I | finSupp 0 h
219 196 218 ffvelcdmd φ g M p P q P y h 0 I | finSupp 0 h g y q Base R
220 219 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
221 193 194 220 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
222 52 ad3antrrr φ g M p P q P Base I mPwSer R = Base R h 0 I | finSupp 0 h
223 221 222 eleqtrrd φ g M p P q P y h 0 I | finSupp 0 h g y q Base I mPwSer R
224 84 adantlr φ g M p P q P finSupp 0 R y h 0 I | finSupp 0 h g y q
225 14 50 51 82 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
226 223 224 225 sylanbrc φ g M p P q P y h 0 I | finSupp 0 h g y q M
227 194 mptexd φ g M p P q P x h 0 I | finSupp 0 h g x p q V
228 150 191 192 226 227 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
229 149 228 eqtrd φ g M p P q P p A q A g = x h 0 I | finSupp 0 h g x p q
230 simpr d = p q f = g f = g
231 coeq2 d = p q x d = x p q
232 231 adantr d = p q f = g x d = x p q
233 230 232 fveq12d d = p q f = g f x d = g x p q
234 233 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
235 234 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
236 160 6 syl φ g M p P q P S Grp
237 simpr φ g M p P q P q P
238 2 140 236 192 237 grpcld φ g M p P q P p + S q P
239 142 238 eqeltrrd φ g M p P q P p q P
240 simpllr φ g M p P q P g M
241 194 mptexd φ g M p P q P x h 0 I | finSupp 0 h g x p q V
242 150 235 239 240 241 ovmpod φ g M p P q P p q A g = x h 0 I | finSupp 0 h g x p q
243 147 229 242 3eqtr4rd φ g M p P q P p q A g = p A q A g
244 143 243 eqtrd φ g M p P q P p + S q A g = p A q A g
245 244 anasss φ g M p P q P p + S q A g = p A q A g
246 245 ralrimivva φ g M p P q P p + S q A g = p A q A g
247 139 246 jca φ g M 0 S A g = g p P q P p + S q A g = p A q A g
248 247 ralrimiva φ g M 0 S A g = g p P q P p + S q A g = p A q A g
249 2 140 132 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
250 7 9 103 248 249 syl22anbrc φ A S GrpAct M