From a logician's standpoint, a "proposition" is a statement that defines an idea or concept. This statement can refer to an idea that is tangible (e.g. the dog is hungry)
http://www.ehow.com/about_6322654_inversestatemen...

if A then B (original) if not A then not B (inverse)
http://wiki.answers.com/Q/What_is_the_inverse_of_t...

The inverse of the statement If p, then q, is the statement If not p,
http://www.chacha.com/question/whatistheinverse...

If you are 25 years old then you are not a teenager.
http://answers.yahoo.com/question/index?qid=201009...
