Given the statement "if ,
then ," or , the converse is "if , then ."
For example, the converse of "If a thing is a dog then it is a mammal" is "If a thing is a mammal then it is a dog." The converse of a theorem
is a theorem if and only if
and are equivalent, i.e., .
,
then 
," or 
, the converse is "if 
, then 
."
and 
are equivalent, i.e., 
.
