1) Α===>Β............................................ ......................given

2) B====>C........................................... ........................given

3) A................................................. ...........................assumption

4) B................................................. ..........................1,3 M.Ponens

5) C................................................. ...........................2,4 M.Ponens

6) A=====>C.......................................... ..................BY using the deduction theorem or called differently the law of conditional proof

from the lines 3 to 5