A
B
(A
⊃
B)
(
B
⊃
A
)
(A
⊃
B)
⊃
(
B
⊃
A
)
T
T
T
T
T
T
F
F
T
T
F
T
T
F
F
F
F
T
T
T
Logical Status:
contingency