30.3 Images under Mappings

  • ImagesSource( map ) A

    is the set of images of the source of the general mapping map.

    ImagesSource delegates to ImagesSet, it is introduced only to store the image of map as attribute value.

  • ImagesRepresentative( map, elm ) O

    If elm is an element of the source of the general mapping map then ImagesRepresentative returns either a representative of the set of images of elm under map or fail, the latter if and only if elm has no images under map.

    Anything may happen if elm is not an element of the source of map.

  • ImagesElm( map, elm ) O

    If elm is an element of the source of the general mapping map then ImagesElm returns the set of all images of elm under map.

    Anything may happen if elm is not an element of the source of map.

  • ImagesSet( map, elms ) O

    If elms is a subset of the source of the general mapping map then ImagesSet returns the set of all images of elms under map.

    Anything may happen if elms is not a subset of the source of map.

  • ImageElm( map, elm ) O

    If elm is an element of the source of the total and single-valued mapping map then ImageElm returns the unique image of elm under map.

    Anything may happen if elm is not an element of the source of map.

  • Image( map ) F
  • Image( map, elm ) F
  • Image( map, coll ) F

    Image( map ) is the image of the general mapping map, i.e., the subset of elements of the range of map that are actually values of map. Note that in this case the argument may also be multi-valued.

    Image( map, elm ) is the image of the element elm of the source of the mapping map under map, i.e., the unique element of the range to which map maps elm. This can also be expressed as elm ^ map. Note that map must be total and single valued, a multi valued general mapping is not allowed (see Images).

    Image( map, coll ) is the image of the subset coll of the source of the mapping map under map, i.e., the subset of the range to which map maps elements of coll. coll may be a proper set or a domain. The result will be either a proper set or a domain. Note that in this case map may also be multi-valued.

    Image delegates to ImagesSource when called with one argument, and to ImageElm resp. ImagesSet when called with two arguments.

    If the second argument is not an element or a subset of the source of the first argument, an error is signalled.

  • Images( map ) F
  • Images( map, elm ) F
  • Images( map, coll ) F

    Images( map ) is the image of the general mapping map, i.e., the subset of elements of the range of map that are actually values of map.

    Images( map, elm ) is the set of images of the element elm of the source of the general mapping map under map, i.e., the set of elements of the range to which map maps elm.

    Images( map, coll ) is the set of images of the subset coll of the source of the general mapping map under map, i.e., the subset of the range to which map maps elements of coll. coll may be a proper set or a domain. The result will be either a proper set or a domain.

    Images delegates to ImagesSource when called with one argument, and to ImagesElm resp. ImagesSet when called with two arguments.

    If the second argument is not an element or a subset of the source of the first argument, an error is signalled.

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    GAP 4 manual
    February 2000