How to input the stabilizer type of D12 × D12-orbits

Let f be a tone row, then its stabilizer U is the set of all (φ,π) ∈ D12 × D12 so that (φ,π)f=f. It is a subgroup of D12 × D12. The stabilizer of any element of the D12 × D12-orbit of f belongs to the conjugacy class of U. Hence, the conjugacy class of U is called the stabilizer type of this orbit.

There are 17 different conjugacy classes of subgroups of D12 × D12 which occur as stabilizers of tone rows. For each class Ũi we present the generator of one representative of this class, the order of this representative, the size of the class, i.e. the number of different groups in this conjugacy class, and the number of D12 × D12-orbits of tone rows with stabilizer type Ũi.

In order to search for tone rows with given stabilizer type, determine the conjugacy class of the stabilizer by choosing a number from {1,…,17}.

name generators size of the group size of the class size of orbit
U1 identity 1 1 827282
U2 (TI,S6) 2 6 912
U3 (T6,R) 2 6 912
U4 (T6,S6) 2 1 130
U5 (I,SR) 2 36 942
U6 (TI,R) 2 36 5649
U7 (T4,S4) 3 2 11
U8 (T3,S3) 4 2 2
U9 (TI,S6), (T6,R) 4 36 96
U10 (I,SR), (T6,S6) 4 18 12
U11 (TI,R), (T6,S6) 4 18 42
U12 (I,SR), (T4,S4) 6 24 2
U13 (TI,R), (T4,S4) 6 24 15
U14 (I,SR), (T3,S3) 8 36 6
U15 (TI,R), (T2,S2) 12 12 2
U16 (I,SR), (T,S) 24 12 1
U17 (I,SR), (T,S5) 24 12 1
where S and R are acting on the domain and T and I are acting on the range.

S is the cyclic shift S=(1,2,3,4,5,6,7,8,9,10,11,12)
R is the retrograde (consisting of 6 transpositions) R=(1,12)(2,11)(3,10)(4,9)(5,8)(6,7).
Then SR is a retrograde inversion (consisting of 5 transpositions and two fixed points) SR=(1)(2,12)(3,11)(4,10)(5,9)(6,8)(7).

T is the transposing operator T=(1,2,3,4,5,6,7,8,9,10,11,12)
I is the inversion at pitch class 1 (consisting of 5 transpositions and two fixed points) I=(1)(2,12)(3,11)(4,10)(5,9)(6,8)(7).
Then TI is an inversion (consisting of 6 transpositions) TI=(1,2)(3,12)(4,11)(5,10)(6,9)(7,8).


Database on tone rows and tropes
harald.fripertinger "at" uni-graz.at
January 2, 2019