Relations Flashcards
(15 cards)
A _____ from set A to set B is a subset of A x B.
(binary) relation R
_____ is some rule that relates a to b.
R
There is _____ to how many b’s are related to each a nor how many a’s are related to each b.
no restriction
A relation R on a set X is a subset of A x B.
Relations
It is the set of all pre-images a related to some b.
Domain
It is the set of all images b related from
some a.
Range
A relational ______ consists of tables.
database
Each _____ is an n-tuple whose ith value is from the set of all possible values of the ith field.
record
The _____ of a relation R on a property P is the smallest superset of R that has the property P.
closure
It is the name given to a subset of some equivalence relation R which includes all elements that are equivalent to each other.
Equivalence Class
Two integers a and b are ______ if and only if they have the same remainder when divided by m.
Congruence Module m
A relation R on set A is a/an _____ if and only if R is reflexive, symmetric, and transitive.
Equivalence Relation
It is the smallest reflexive relation of the set A that contains R.
Reflexive closure
It is the smallest symmetric relation on a set A that contains R.
Symmetric closure
It is the smallest transitive relation on a set A that contains R.
Transitive closure
