 The Hamacher t-norm formula_12 is strict if and only if "p" < +∞ (for "p" = 1 it is the product t-norm).The family is strictly decreasing and continuous with respect to "p".An additive generator of formula_12 for "p" < +∞ is

The family of "Frank t-norms", introduced by M.J. Frank in the late 1970s, is given by the parametric definition for 0 ≤ "p" ≤ +∞ as follows