1. The problem statement, all variables and given/known data 1. Is there any difference between the following 2 signs? <=> (for biconditional) and 三(the equivalence sign) 2. When we say 'P is defined as Q), do we mean P三Q? Thanks J 2. Relevant equations 3. The attempt at a solution It seems that for 2 propositions, P & Q: (i) P三Q when 'P and Q have the same kinds and numbers of components' and 'their truth values are equivalent' (ii) P <=> Q is expressing the same thing as above.