Theorems for Free (1989) [pdf]

I presume your post attracted little attention because people either didn't know what it was from the title, or for those who did, it's perhaps too familiar.

So a small explanation: in the functional community it's a famous classic paper; by Philip Wadler. Abstract:

"From the type of a polymorphic function we can derive a theorem that it satisfies. Every function of the same type satisfies the same theorem. This provides a free source of useful theorems, courtesy of Reynolds' abstraction theorem for the polymorphic lambda calculus."

It "gave rise to much research on functional language optimization" http://en.wikipedia.org/wiki/Philip_Wadler

See also http://en.wikipedia.org/wiki/Parametricity