二、归结法证明举例
例1:(
x)(P(x)→Q(x))∧(
x)(Q(x)→R(x))
(
x)(P(x)→R(x))
例2:A1 = (
x)(P(x)∧(
y)(D(y)→L(x, y)))
A2 =(
x)(P(x)→(
y)(Q(y)→
(L(x, y)))
B = (
x)(D(x)→
Q(x))
求证 A1∧A2
B
x)(P(x)→Q(x))∧(x)(Q(x)→R(x))
(x)(P(x)→R(x))
x)(P(x)∧(y)(D(y)→L(x,
y)))x)(P(x)→(y)(Q(y)→
(L(x,
y)))x)(D(x)→Q(x))B