38.7 Permutations Induced by Elements and Cycles

If only the permutation image of a single element is needed, it might not be worth to create the action homomorphism, the following operations yield the permutation image and cycles of a single element.

  • Permutation( g, Omega[, gens, acts][, act] ) F
  • Permutation( g, xset ) F

    computes the permutation that corresponds to the action of g on the domain Omega or the UnderlyingDomain value of the external set xset, respectively. If g does not leave the domain invariant, or does not map injectively, fail is returned.

  • PermutationCycle( g, Omega, pnt[, act] ) O

    computes the permutation that represents the cycle of pnt under the action of the elemnt g

    gap> Permutation((1,2,3)(4,5)(6,7),[4..7]);       
    (1,2)(3,4)
    gap> PermutationCycle((1,2,3)(4,5)(6,7),[4..7],4);
    (1,2)
    
  • Cycle( g, Omega, pnt[, act] ) O

    returns a list of the points in the cycle of pnt under the action of the element g.

  • CycleLength( g, Omega, pnt[, act] ) O

    returns the length of the cycle of pnt under the action of the element g.

  • Cycles( g, Omega[, act] ) O

    returns a list of the cycles (as lists of points) of the action of the element g.

  • CycleLengths( g, Omega, [, act] ) O

    returns the lengths of all the cycles under the action of the element g on Omega.

    gap> Cycle((1,2,3)(4,5)(6,7),[4..7],4);
    [ 4, 5 ]
    gap> CycleLength((1,2,3)(4,5)(6,7),[4..7],4);
    2
    gap> Cycles((1,2,3)(4,5)(6,7),[4..7]);       
    [ [ 4, 5 ], [ 6, 7 ] ]
    gap> CycleLengths((1,2,3)(4,5)(6,7),[4..7]);
    [ 2, 2 ]
    

    [Top] [Previous] [Up] [Next] [Index]

    GAP 4 manual
    February 2000