Includes the relations (a, b) for all b in bs.
Includes the relation (a, b).
Includes the relation given by pair
.
Includes the given relations.
Returns the union of the relation r with this relation.
Removes pair
from this relation.
Removes all pairs (_1, _2) from this relation.
Removes all pairs
from this relation.
Removes all relations (_1, _2) for all _1 in _1s.
Returns the set of all _1s such that (_1, _2) is in this relation.
Returns the set of all _2s such that (_1, _2) is in this relation.
Returns all pairs in this relation.
Returns true iff (a,b) is in this relation
Returns a relation with only pairs (a,b) for which f(a,b) is true.
Returns the set of all _2s such that (_1, _2) is in this relation.
Returns the set of all _1s such that (_1, _2) is in this relation.
Returns the number of pairs in this relation
Binary relation between A and B. It is a set of pairs (_1, _2) for _1 in A, _2 in B.