3.3. COMBINING FUZZY SETS 97
Table 3.1 (a). Strict t-norms,a> 0 ,r> 0
Type t-norm generator
Algebraic product xy xHamacher
xy
a+(1−a)(x+y−xy)(
x
a−(a−1)x a>^0
ex− 1
x a=0Frank loga≥
1+(ax−1)(ay−1)
a− 1¥
,a 6 =1
ax− 1
a− 1
Schweizer-Sklar (x−a+y−a−1)
−a^1
exp≥
−^1 −xa
(2a−1)xa¥
Schweizer-Sklar 1 −((1−x)a+(1−y)a 1 −(1−x)a
−(1−x)a(1−y)a)(^1) a
AczÈl-Alsina e−((−lnx)
a+(−lny)a)a^1
e−r(−lnx)
a
,r> 0
Dombi
≥
1+
≥°
1 −x
x¢a
+≥
1 −y
y¥
a¥ 1
a¥− 1
e−(1 −xx)a1-parameter family xye−alnxlny1
1 −alnx
2-parameter family≥
1+[(^1 −xx)r+(^1 −yy)r°
1+a° 1 −x
x¢r¢− 1+a((^1 −xx)r(^1 −yy)r](^1) r¥−^1
Table 3.1 (b). Strict t-conorms,a> 0 ,r> 0
Type t-conorm cogenerator
Algebraic sum x+y−xy 1 −x
Hamacher
x+y+(a−2)xy
1+(a−1)xy
Ω 1 −x
1+(a−1)x a>^0
e
1 −xx
a=0
Frank,a 6 =1 1 −loga
μ
1+
(a^1 −x−^1 )(a^1 −y−^1 )
a− 1
∂
a^1 −x− 1
a− 1Schweizer-Sklar 1 −((1−x)−a+(1−y)−a−1)−(^1) a
exp
≥
−^1 −(1−x)a
(2a−1)(1−x)a¥
Schweizer-Sklar (xa+ya−xaya)(^1) a
1 −xa
AczÈl-Alsina e−((−lnx)
a+(−lny)a)^1 a
e−r(−lnx)
a
Dombi
μ
1+
≥°
1 −x
x¢a
+≥
1 −y
y¥a¥^1 a∂−^1
e−(1 −xx)a1-parameter family 1 −(1−x)(1−y)e−aln(1−x)ln(1−y)1
1 −aln (1−x)
2-parameter family≥
1+
≥
(^1 −xx)r+(^1 −yy)r°
1+a° 1 −x
x¢r¢− 1+a((^1 −xx)r(^1 −yy)r¥r^1 ∂−^1