Converse seems to be logically equivalent to conditional

discrete mathematicslogicpredicate-logic

This is part of a question (PS: the question just asked me to write converse, inverse, contrapositive counterparts. My question is not related to the question itself):

Statement: ∀n ∈ Z, if (6 | n), then (2 | n) and (3 | n).

Converse: ∀n
∈ Z, if (2 | n) and (3 | n), then (6 | n).

I understand that converse statements are NOT logically equivalent to conditional statements.

For them to be logically inequivalent, we just need one instance where predicates have opposite truth values for a particular chosen value of the predicate variable.

But I'm unable to find that one instance (counter-example) that would prove that the converse and the original are not logically equivalent.

Best Answer

For your statement, the converse is true since $\mathrm{lcm}(2,3)=6$ but it isn't always.

$\forall\ n \in \mathbb{Z},$ if $12 \mid n,$ then $2 \mid n$ and $3 \mid n$ but the converse is not true.

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