deduction theorem
in a complete formal system, in order to prove 
we can add 
to the set of assumptions and then prove 
a special case of the deduction theorem is:
iff 
when writing a formal proof, we write
(atleast in my college) to denote the usage of deduction theorem
we can add to the set of assumptions and then prove
a special case of the deduction theorem is:
iff
when writing a formal proof, we write
(atleast in my college) to denote the usage of deduction theorem
infer 
from 
from