Justification for Deducing Biconditionality
Let us say that I want to prove the biconditional a ↔ b. At some point in proof, I show a → b, and at some other
point, I show b → a. I then combine these on one line via conjunction: (a → b) & (b → a). I want the next step to
be a ↔ b. What justification would I use for thisl step? I was thinking of something like "definition of
biconditionality" but that doesn't seem quite right. Something about calling it a "definition" seems inappropriate.
point, I show b → a. I then combine these on one line via conjunction: (a → b) & (b → a). I want the next step to
be a ↔ b. What justification would I use for thisl step? I was thinking of something like "definition of
biconditionality" but that doesn't seem quite right. Something about calling it a "definition" seems inappropriate.