  This paper deals with conditions under which the quotient of $L$-fuzzy
up-sets forms a complete lattice by using terminologies of closure operators.
It first gives a condition that a family of some subsets of a nonempty set can
be represented by $L$-fuzzy up-sets, which is then used to formulate a
necessary and sufficient condition under which the quotient of $L$-fuzzy
up-sets forms a complete lattice. This paper finally shows that the quotient of
a kind of $L$-fuzzy up-sets is isomorphic to an interval generated by an
$L$-fuzzy up-set.

Logic;Logic in Computer Science