“…The unique solvability of a system of sup-T equations, as well as the existence of the minimum solution, was investigated by Di Sessa (1983, 1988), Sessa (1984), Liguori (1984, 1985), Cechlárová (1990Cechlárová ( , 1995, Li (1990), Gavalec (2001) and Gavalec and Plávka (2003). Various estimates of the number of the minimal solutions can be found in Czogała et al (1982), Wang et al (1984), Shi (1987), Peeva (1992Peeva ( , 2006 and Kyosev (2004, 2007).…”