GroupTheory
WreathProduct
form the wreath product of groups
RegularWreathProduct
form the regular wreath product of groups
Calling Sequence
Parameters
Description
Examples
WreathProduct( G, H, ... )
RegularWreathProduct( G, H, ... )
G,H, ...
-
two or more permutation groups
Let G and H be permutation groups. The wreath product G ≀ H_ of G by H is a permutation group constructed as a semi-direct product of d copies of G (called the base group), where d is the degree of H, and the action of H on the base group is the action of H by permuting the copies of G. Thus, the order of G ≀ H_ is equal to Gd⁢H, and the degree of the wreath product is the product of the degrees of G and H.
The regular wreath product of G and H is the wreath product in which H is considered as a regular permutation group on itself. (This is also called the "standard wreath product".)
The WreathProduct( G, H ) command returns a permutation group that is the wreath product G ≀ H_.
If more than two groups are provided as input, then an iterated wreath product is constructed using the left associative rule. For example, WreathProduct( A, B, C, D ) returns ((A ≀ B) ≀ C) ≀ D_.
The RegularWreathProduct( G, H ) command returns the regular wreath product of G and H. In this case, it is not required that H be a permutation group, as a regular permutation representation of the finite group H is used instead. (Here, H may be either a Cayley table group or a finitely presented finite group, as well as a permutation group, which need not be itself regular.)
with⁡GroupTheory:
G≔WreathProduct⁡CyclicGroup⁡2,CyclicGroup⁡2
G≔1,2,1,32,4
AreIsomorphic⁡G,DihedralGroup⁡4
true
Iterated wreath products appear naturally as Sylow subgroups of symmetric groups of prime power degree.
AreIsomorphic⁡WreathProduct⁡CyclicGroup⁡3,CyclicGroup⁡3,SylowSubgroup⁡3,Symm⁡9
AreIsomorphic⁡WreathProduct⁡`$`⁡CyclicGroup⁡2,3,SylowSubgroup⁡2,Symm⁡23
Note that iterated wreath products grow quite rapidly.
GroupOrder⁡WreathProduct⁡CyclicGroup⁡3,CyclicGroup⁡3
81
GroupOrder⁡WreathProduct⁡CyclicGroup⁡3,CyclicGroup⁡3,CyclicGroup⁡3
1594323
GroupOrder⁡WreathProduct⁡CyclicGroup⁡3,CyclicGroup⁡3,CyclicGroup⁡3,CyclicGroup⁡3
12157665459056928801
GroupOrder⁡WreathProduct⁡CyclicGroup⁡3,CyclicGroup⁡3,CyclicGroup⁡3,CyclicGroup⁡3,CyclicGroup⁡3
5391030899743293631239539488528815119194426882613553319203
W≔WreathProduct⁡Alt⁡4,Symm⁡3
W≔1,2,3,2,3,4,1,52,63,74,8,1,5,92,6,103,7,114,8,12
GroupOrder⁡W
10368
The wreath product construction is not commutative; notice that even the order is different.
GroupOrder⁡WreathProduct⁡Symm⁡3,Alt⁡4
15552
Note that the regular wreath product is also different in this case, since the second argument here is not the regular permutation representation of the symmetric group.
GroupOrder⁡RegularWreathProduct⁡Alt⁡4,Symm⁡3
17915904
Since both S3 and A4 are transitive, so too is their wreath product.
IsTransitive⁡W
However, in general, the wreath product is not primitive.
IsPrimitive⁡W
false
BlockSystem⁡W
1,2,3,4,5,6,7,8,9,10,11,12
Here we construct a wreath product with an intransitive second argument.
W≔WreathProduct⁡Alt⁡4,Group⁡Perm⁡1,2,3,4:
The resulting group is not transitive.
map⁡Elements,Orbits⁡W
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16
Here we construct a wreath product with an intransitive first argument.
W≔WreathProduct⁡Group⁡Perm⁡1,2,3,4,Symm⁡3:
Again, the result is an intransitive group.
1,2,5,6,9,10,3,4,7,8,11,12
W≔RegularWreathProduct⁡CyclicGroup⁡2,a,b|a2,b3,a·b5=1
W≔1,2,1,32,45,136,147,158,169,1710,1811,1912,2021,3722,3823,3924,4025,4126,4227,4328,4429,4530,4631,4732,4833,4934,5035,5136,5253,7354,7455,7556,7657,5958,6061,7762,7863,7964,8065,8166,8267,6968,7071,8372,8485,10786,10887,8988,9091,10992,11093,11194,11295,9796,9899,101100,102103,113104,114105,115106,116117,119118,120,1,5,72,6,83,9,114,10,1213,21,2314,22,2415,25,2716,26,2817,29,3118,30,3219,33,3520,34,3637,51,5338,52,5439,55,5740,56,5841,59,6142,60,6243,63,4544,64,4647,65,6748,66,6849,69,7150,70,7273,85,8774,86,8875,89,9176,90,9277,93,9578,94,9679,97,9980,98,10081,101,10382,102,10483,105,10784,106,108109,117,111110,118,112113,119,115114,120,116
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120
S≔Stabilizer⁡109,W:
Index⁡S,W
120
GroupOrder⁡S
576460752303423488
IsElementary⁡S
DirectFactors⁡S
119,120,119,120,119,120,119,120,119,120,119,120,119,120,119,120,119,120,119,120,119,120,119,120,119,120,119,120,119,120,119,120,119,120,119,120,119,120,119,120,119,120,119,120,119,120,119,120,119,120,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,117,118,115,116,115,116,115,116,115,116,115,116,115,116,115,116,115,116,115,116,115,116,115,116,115,116,115,116,115,116,115,116,115,116,115,116,115,116,115,116,115,116,115,116,115,116,115,116,115,116,115,116,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,113,114,111,112,111,112,111,112,111,112,111,112,111,112,111,112,111,112,111,112,111,112,111,112,111,112,111,112,111,112,111,112,111,112,111,112,111,112,111,112,111,112,111,112,107,108,107,108,107,108,107,108,107,108,107,108,107,108,107,108,107,108,107,108,107,108,107,108,107,108,107,108,107,108,107,108,107,108,107,108,107,108,107,108,107,108,107,108,107,108,107,108,107,108,107,108,107,108,105,106,105,106,105,106,105,106,105,106,105,106,105,106,105,106,105,106,105,106,105,106,105,106,105,106,105,106,105,106,105,106,105,106,105,106,105,106,105,106,105,106,105,106,105,106,105,106,105,106,105,106,105,106,103,104,103,104,103,104,103,104,103,104,103,104,103,104,103,104,103,104,103,104,103,104,103,104,103,104,103,104,103,104,103,104,103,104,103,104,103,104,103,104,103,104,103,104,103,104,103,104,103,104,103,104,103,104,103,104,101,102,101,102,101,102,101,102,101,102,101,102,101,102,101,102,101,102,101,102,101,102,101,102,101,102,101,102,101,102,101,102,101,102,101,102,101,102,101,102,101,102,101,102,101,102,101,102,101,102,101,102,99,100,99,100,99,100,99,100,99,100,99,100,99,100,99,100,99,100,99,100,99,100,99,100,99,100,99,100,99,100,99,100,99,100,99,100,99,100,99,100,99,100,99,100,99,100,99,100,99,100,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,97,98,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,95,96,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,93,94,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,91,92,89,90,89,90,89,90,89,90,89,90,89,90,89,90,89,90,89,90,89,90,89,90,89,90,89,90,89,90,89,90,89,90,89,90,89,90,89,90,89,90,89,90,89,90,89,90,89,90,89,90,89,90,89,90,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,87,88,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,85,86,83,84,83,84,83,84,83,84,83,84,83,84,83,84,83,84,83,84,83,84,83,84,83,84,83,84,83,84,83,84,83,84,83,84,83,84,83,84,83,84,83,84,83,84,83,84,83,84,83,84,83,84,81,82,81,82,81,82,81,82,81,82,81,82,81,82,81,82,81,82,81,82,81,82,81,82,81,82,81,82,81,82,81,82,81,82,81,82,81,82,81,82,81,82,81,82,81,82,81,82,81,82,81,82,81,82,81,82,79,80,79,80,79,80,79,80,79,80,79,80,79,80,79,80,79,80,79,80,79,80,79,80,79,80,79,80,79,80,79,80,79,80,79,80,79,80,79,80,79,80,79,80,79,80,79,80,79,80,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,77,78,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,75,76,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,73,74,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,71,72,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,69,70,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,67,68,65,66,65,66,65,66,65,66,65,66,65,66,65,66,65,66,65,66,65,66,65,66,65,66,65,66,65,66,65,66,65,66,65,66,65,66,65,66,65,66,65,66,65,66,65,66,65,66,65,66,65,66,63,64,63,64,63,64,63,64,63,64,63,64,63,64,63,64,63,64,63,64,63,64,63,64,63,64,63,64,63,64,63,64,63,64,63,64,63,64,63,64,63,64,63,64,63,64,63,64,63,64,63,64,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,61,62,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,59,60,29,30,29,30,29,30,29,30,29,30,29,30,29,30,29,30,29,30,29,30,29,30,29,30,29,30,29,30,29,30,29,30,29,30,29,30,29,30,29,30,29,30,29,30,29,30,29,30,29,30,29,30,27,28,27,28,27,28,27,28,27,28,27,28,27,28,27,28,27,28,27,28,27,28,27,28,27,28,27,28,27,28,27,28,27,28,27,28,27,28,27,28,27,28,27,28,27,28,27,28,27,28,27,28,27,28,27,28,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,25,26,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,23,24,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,21,22,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,19,20,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,17,18,15,16,15,16,15,16,15,16,15,16,15,16,15,16,15,16,15,16,15,16,15,16,15,16,15,16,15,16,15,16,15,16,15,16,15,16,15,16,15,16,15,16,15,16,15,16,15,16,15,16,15,16,15,16,13,14,13,14,13,14,13,14,13,14,13,14,13,14,13,14,13,14,13,14,13,14,13,14,13,14,13,14,13,14,13,14,13,14,13,14,13,14,13,14,13,14,13,14,13,14,13,14,13,14,13,14,13,14,13,14,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,3,4,5,6,5,6,5,6,5,6,5,6,5,6,5,6,5,6,5,6,5,6,5,6,5,6,5,6,5,6,5,6,5,6,5,6,5,6,5,6,5,6,5,6,5,6,5,6,5,6,5,6,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,7,8,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,9,10,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,11,12,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,31,32,33,34,33,34,33,34,33,34,33,34,33,34,33,34,33,34,33,34,33,34,33,34,33,34,33,34,33,34,33,34,33,34,33,34,33,34,33,34,33,34,33,34,33,34,33,34,33,34,35,36,35,36,35,36,35,36,35,36,35,36,35,36,35,36,35,36,35,36,35,36,35,36,35,36,35,36,35,36,35,36,35,36,35,36,35,36,35,36,35,36,35,36,35,36,35,36,35,36,35,36,35,36,35,36,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,37,38,39,40,39,40,39,40,39,40,39,40,39,40,39,40,39,40,39,40,39,40,39,40,39,40,39,40,39,40,39,40,39,40,39,40,39,40,39,40,39,40,39,40,39,40,39,40,41,42,41,42,41,42,41,42,41,42,41,42,41,42,41,42,41,42,41,42,41,42,41,42,41,42,41,42,41,42,41,42,41,42,41,42,41,42,41,42,41,42,41,42,41,42,41,42,41,42,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,43,44,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,45,46,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,47,48,49,50,49,50,49,50,49,50,49,50,49,50,49,50,49,50,49,50,49,50,49,50,49,50,49,50,49,50,49,50,49,50,49,50,49,50,49,50,49,50,49,50,49,50,49,50,49,50,49,50,49,50,49,50,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,51,52,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,53,54,55,56,55,56,55,56,55,56,55,56,55,56,55,56,55,56,55,56,55,56,55,56,55,56,55,56,55,56,55,56,55,56,55,56,55,56,55,56,55,56,55,56,55,56,55,56,55,56,55,56,55,56,57,58,57,58,57,58,57,58,57,58,57,58,57,58,57,58,57,58,57,58,57,58,57,58,57,58,57,58,57,58,57,58,57,58,57,58,57,58,57,58,57,58,57,58,57,58,57,58,57,58,57,58,57,58
Notice that, if a group is already regular, then its regular wreath product is isomorphic to the ordinary wreath product.
R≔TransitiveGroup⁡6,2
R≔1,3,52,4,6,1,42,35,6
IsRegular⁡R
AreIsomorphic⁡WreathProduct⁡CyclicGroup⁡2,R,RegularWreathProduct⁡CyclicGroup⁡2,R
See Also
GroupTheory[AlternatingGroup]
GroupTheory[AreIsomorphic]
GroupTheory[CyclicGroup]
GroupTheory[DihedralGroup]
GroupTheory[DirectProduct]
GroupTheory[GroupOrder]
GroupTheory[IsPrimitive]
GroupTheory[IsTransitive]
GroupTheory[Orbits]
GroupTheory[SymmetricGroup]
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