Lattice of fuzzy subalgebras and closure systems in I x

Abstract Let X be a non-empty set and I be the unit interval of real numbers. The elements of I x are called fuzzy subsets of X . I x is a lattice with the pointwise ordering of I . Now if A = [ X , F ] is an universal algebra with a specified set F of finitary operations on X , then each operation can be extended to a finitary operation on I x . An element of I x is defined to be a fuzzy subalgebra of A using these extended operations. We also define algebraic closure system in I x . We then show that the lattice of fuzzy subalgebras of A is an algebraic closure system in I x .