Mathematics
F(t) => exists x F(x) から forall x F(x) => F(t) を導く。 (1) F(t) => exists x F(x) (2) ^ exists x F(x) => ^F(t) : [対偶{(1)}] (3) ^ exists x F(x) => forall x ^F(x) : [I2{(2)}] (4) ^ exists x ^F(x) => forall x ^^F(x) : [(3){F -> ^F}] (5) ^…
F(t) => exists x F(x) から forall x F(x) => F(t) を導く。 (1) F(t) => exists x F(x) (2) ^ exists x F(x) => ^F(t) : [対偶{(1)}] (3) ^ exists x F(x) => forall x ^F(x) : [I2{(2)}] (4) ^ exists x ^F(x) => forall x ^^F(x) : [(3){F -> ^F}] (5) ^…