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PermutationList ​

Cycles back to a one-line word: the image list {σ(1),σ(2),… }\{\sigma(1), \sigma(2), \dots\}. PermutationList(perm, n) pads that list with fixed points out to length nn.

✓ checked against that system · ! checked, with disagreements (hover a chip)Wolfram LanguagePermutationList✓
PermutationList(perm)the one-line word, as long as perm's own support
PermutationList(perm, n)the one-line word, padded with fixed points to length nn
Typed signatures
TypePackageApplies
(expression<Cycles>, integer?) -> list<integer>groupalgebraalways

Domain: Permutations

Details
  • Only takes Cycles — a one-line word is already this head's own answer, so there is nothing to convert
  • n shorter than the cycles' own largest point leaves the call unevaluated — there is no room for that point in the result
  • The inverse of PermutationCycles's no-argument form, which reads a one-line word back into cycle notation

Examples

Basic #

the cycle (1 3 2)(1\,3\,2)'s image list runs out to its own largest point, 3

live ↗
InPermutationList(Cycles([[1,3,2]]))\mathrm{PermutationList}(\mathrm{Cycles}(\bigl\lbrack\bigl\lbrack1, 3, 2\bigr\rbrack\bigr\rbrack))Out[3,1,2]\bigl\lbrack3, 1, 2\bigr\rbrack

points 4 and 5 are fixed, so padding to n=5n = 5 just appends them

live ↗
InPermutationList(Cycles([[2,3]]),5)\mathrm{PermutationList}(\mathrm{Cycles}(\bigl\lbrack\bigl\lbrack2, 3\bigr\rbrack\bigr\rbrack), 5)Out[1,3,2,4,5]\bigl\lbrack1, 3, 2, 4, 5\bigr\rbrack

Expands cycles to a one-line list, sized to the largest point

live ↗
InPermutationList(Cycles([[3,2],[1,6,7]]))\mathrm{PermutationList}(\mathrm{Cycles}(\bigl\lbrack\bigl\lbrack3, 2\bigr\rbrack, \bigl\lbrack1, 6, 7\bigr\rbrack\bigr\rbrack))Out[6,3,2,4,5,7,1]\bigl\lbrack6, 3, 2, 4, 5, 7, 1\bigr\rbrack

A length argument pads the list with fixed points

live ↗
InPermutationList(Cycles([[3,2],[1,6,7]]),9)\mathrm{PermutationList}(\mathrm{Cycles}(\bigl\lbrack\bigl\lbrack3, 2\bigr\rbrack, \bigl\lbrack1, 6, 7\bigr\rbrack\bigr\rbrack), 9)Out[6,3,2,4,5,7,1,8,9]\bigl\lbrack6, 3, 2, 4, 5, 7, 1, 8, 9\bigr\rbrack
Scope #

Length follows the largest point moved, here 9

live ↗
InPermutationList(Cycles([[1,5],[2,9,3]]))\mathrm{PermutationList}(\mathrm{Cycles}(\bigl\lbrack\bigl\lbrack1, 5\bigr\rbrack, \bigl\lbrack2, 9, 3\bigr\rbrack\bigr\rbrack))Out[5,9,2,4,1,6,7,8,3]\bigl\lbrack5, 9, 2, 4, 1, 6, 7, 8, 3\bigr\rbrack

The identity with no length gives an empty list

live ↗
InPermutationList(Cycles([]))\mathrm{PermutationList}(\mathrm{Cycles}(\bigl\lbrack\bigr\rbrack))Out[]\bigl\lbrack\bigr\rbrack

The identity at a given length is 1,2,…,101, 2, \dots, 10

live ↗
InPermutationList(Cycles([]),10)\mathrm{PermutationList}(\mathrm{Cycles}(\bigl\lbrack\bigr\rbrack), 10)Out[1,2,3,4,5,6,7,8,9,10]\bigl\lbrack1, 2, 3, 4, 5, 6, 7, 8, 9, 10\bigr\rbrack
Properties #

PermutationList and PermutationCycles undo each other

live ↗
InPermutationCycles(PermutationList(Cycles([[1,2,5],[4,6,8,9]])))\mathrm{PermutationCycles}(\mathrm{PermutationList}(\mathrm{Cycles}(\bigl\lbrack\bigl\lbrack1, 2, 5\bigr\rbrack, \bigl\lbrack4, 6, 8, 9\bigr\rbrack\bigr\rbrack)))OutCycles([[1,2,5],[4,6,8,9]])\mathrm{Cycles}(\bigl\lbrack\bigl\lbrack1, 2, 5\bigr\rbrack, \bigl\lbrack4, 6, 8, 9\bigr\rbrack\bigr\rbrack)

Inverse of PermutationCycles: the round trip recovers the list

live ↗
InPermutationList(PermutationCycles([6,3,5,4,2,7,8,1]))\mathrm{PermutationList}(\mathrm{PermutationCycles}(\bigl\lbrack6, 3, 5, 4, 2, 7, 8, 1\bigr\rbrack))Out[6,3,5,4,2,7,8,1]\bigl\lbrack6, 3, 5, 4, 2, 7, 8, 1\bigr\rbrack

Each position holds the image of that point

live ↗
InPermutationList(Cycles([[1,2,3],[4,5]]))\mathrm{PermutationList}(\mathrm{Cycles}(\bigl\lbrack\bigl\lbrack1, 2, 3\bigr\rbrack, \bigl\lbrack4, 5\bigr\rbrack\bigr\rbrack))Out[2,3,1,5,4]\bigl\lbrack2, 3, 1, 5, 4\bigr\rbrack

Untouched point 3 stays in place

live ↗
InPermutationList(Cycles([[1,5,6],[2,4]]))\mathrm{PermutationList}(\mathrm{Cycles}(\bigl\lbrack\bigl\lbrack1, 5, 6\bigr\rbrack, \bigl\lbrack2, 4\bigr\rbrack\bigr\rbrack))Out[5,4,3,2,6,1]\bigl\lbrack5, 4, 3, 2, 6, 1\bigr\rbrack
About
Examples11
Checked againstWolfram Language 11 agree
CrosswalkWolfram Language

See also: Cycles, PermutationCycles, Permute, PermutationReplace