Solutions to Homework #9, Problems 23-29

Since we know that C true, then can assert a disjunction C ( D because it doesn’t matter whether D is true or not, by the definition of (. Now assume B. This, together with B ( D imply D, by modus ponens. Since we know that D is true, then we can assert a disjunction C ( D because it doesn’t matter whether C is true or not, by the ... ................
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