A double coset is represented by a domain record with the following tag components.
isDomain:true.
isDoubleCoset:true.
The double coset is determined by the following identity components, which every double coset must have.
leftGroup:
rightGroup:
representative:In addition, a double coset record may have the following optional information components.
rightCosets:
elements:
isFinite:true if the double coset is finite and
false if the double coset is infinite. If not present it is
not known whether the double coset is finite or infinite.
size:GAP 3.4.4