Fuzzy set theory is considered as a suitable setting in order to take vagueness of real world problems into considerations. Operating with fuzzy dependencies among fuzzy data is a challenging problem, because it requires special arithmetic and a powerful optimization technique. The concept of fuzzy numbers and arithmetic operation with these numbers were first introduced and investigated by Zad...

Since the discovery of fuzzy sets, the arithmetic operations of fuzzy numbers (Zadeh [7, 8]) which may be viewed as a generalization of interval arithmetic (Moore [5]) have emerged as an important area of research within the theory of fuzzy sets (Mizumoto and Tanaka [4], Dubois and Prade [2]). The arithmetic operations of fuzzy numbers have been performed either by extension principle [7, 8] or...

Fix coprime natural numbers a,q. Assuming the Prime k-tuple Conjecture, we show that there exist arbitrarily long arithmetic progressions of Carmichael numbers, each which lies in reduced residue class a mod q and is product three distinct prime numbers.