Appendix A Useful Mathematical Formulae
x1−q − 1 ln x ≡ (x > 0, q ∈ R)(A.1) q 1 − q
1−q lnq x = x ln2−q x (x > 0; ∀q)(A.2)
lnq (1/x) + ln2−q x = 0(x > 0; ∀q)(A.3)
q q lnq x + ln(1/q)(1/x ) = 0(x > 0; ∀q)(A.4)
⎧ < < − / − , ⎪ 0ifq 1 and x 1 (1 q) ⎪ ⎪ ⎪ 1 ⎨⎪ + − 1−q < ≥− / − , 1 [1 (1 q) x] if q 1 and x 1 (1 q) x 1−q e ≡ [1 + (1 − q) x]+ ≡ q ⎪ ⎪ ex if q = 1(∀x) , ⎪ ⎪ ⎩ 1 [1 + (1 − q) x] 1−q if q > 1 and x < 1/(q − 1) . (A.5)
x −x = ∀ eq e2−q 1(q)(A.6)
x q −qx = ∀ (eq ) e(1/q) 1(q)(A.7)
x+y+(1−q)xy = x y ∀ eq eq eq ( q)(A.8)
329 330 Appendix A Useful Mathematical Formulae
x ⊕q y ≡ x + y + (1 − q) xy (A.9)
For x ≥ 0 and y ≥ 0: ⎧ −q −q ⎪ 0ifq < 1andx 1 + y1 < 1 , ⎪ ⎪ ⎪ 1 ⎪ 1−q 1−q 1−q 1−q 1−q 1 ⎨ [x + y − 1] if q < 1andx + y ≥ 1 , 1−q 1−q 1−q x ⊗ y ≡ [x + y − 1]+ ≡ q ⎪ ⎪ xy if q = 1 ∀(x, y) , ⎪ ⎪ ⎩ − − 1 − − [x 1 q + y1 q − 1] 1−q if q > 1andx 1 q + y1 q > 1 . (A.10)
1 − x ⊗q y = [1 + (1 − q)(lnq x + lnq y)] 1 q (A.11)
⊕ x q y = x y ∀ eq eq eq ( q) (A.12)
x+y = x ⊗ y ∀ eq eq q eq ( q) (A.13)
d ln x 1 q = (x > 0; ∀q) (A.14) dx xq
dex q = (ex )q (∀q) (A.15) dx q
x q = qx ∀ (eq ) e2−(1/q) ( q) (A.16)
x a = ax ∀ (eq ) e1−(1−q)/a ( q) (A.17)