A set of coefficient matrices which are invariant to a solution set of a simple fuzzy relation equation is considered. The equipollency of the cardinal numbers of solution sets of simple fuzzy relation equations for two constant vectors is also shown. © 1987.
Miyakoshi, M., & Shimbo, M. (1987). Sets of solution-set-invariant coefficient matrices of simple fuzzy relation equations. Fuzzy Sets and Systems, 21(1), 59–83. https://doi.org/10.1016/0165-0114(87)90153-9