Suppose that I know that the following statements hold
- If A, then C;
- If B, then C.
But “if A, then C” AND “if B, then C” is logically equivalent to
- If A or B, then C
So I have two equivalent options when writting a proposition: state items 1 and 2 or state item 3.
Both options are proved in the same way: “Suppose A holds, then we have C… Suppose B holds, then we have C.”
Are these ideas correct?