Resumen de On some geometric transformation of t-norms

Erich Peter Klement, Radko Mesiar, Endre Pap

• Given a triangular norm T, its t-reverse T*, introduced by C. Kimberling (Publ. Math. Debrecen 20, 21-39, 1973) under the name invert, is studied. The question under which conditions we have T** = T is completely solved. The t-reverses of ordinal sums of t-norms are investigated and a complete description of continuous, self-reverse t-norms is given, leading to a new characterization of the continuous t-norms T such that the function G(x,y) = x + y - T(x,y) is a t-conorm, a problem originally studied by M.J. Frank (Aequationes Math. 19, 194-226, 1979). Finally, some open problems are formulated.