Solutions to Homework #9, Problems 23-29

Another way: Let’s suppose that A is the case. Since we are assuming A and know A ( B, by modus ponens, this implies B. However, since we also know (B, this gives us B and (B, a contradiction. Therefore, by reductio ad absurdum, (A. 2. Strenthening the Antecedent: From B ( C infer (A ( B) ( C. In addition to our premise, B ( C, let’s ... ................
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