Solutions to Easy Proofs in QL
Proof 3
1.
(x)Ax
⊃
(
∃
x)Bx
premise
2.
(
∃
x)Bx
⊃
~(x)Cx
premise
3.
(x)Ax
Assump., CP
SP1
4.
(
∃
x)Bx
M.P. 1,3
SP1
5.
~(x)Cx
M.P., 2,4
SP1
6.
(
∃
x)~Cx
Q.N.R., 5
SP1
7.
(x)Ax
⊃
(
∃
x)~Cx
CP, 3-6