A => B, A
---------
B
A1 and A2 and ... An
--------------------
Ai
A1, A2, ... An -------------------- A1 and A2 and ... An
Ai
------------------
A1 or A2 or ... An
NOT(NOT(A))
-----------
A
A or B, NOT(B)
---------------
A
A or B, NOT(B) or C
-------------------
A or C