Observational equivalence

From Wikipedia, the free encyclopedia

The introduction to this article provides insufficient context for those unfamiliar with the subject matter.
Please help improve the introduction to meet Wikipedia's layout standards. You can discuss the issue on the talk page.

Two terms M and N are observationally equivalent if for all contexts C[] where C[M] is a valid term, C[N] is also a valid term with the same value. Thus it is not possible to differentiate between the two terms. If on the other hand one can define a rule that allows us to identify either term, then they are not observationally equivalent.

This article was originally based on material from the Free On-line Dictionary of Computing, which is licensed under the GFDL.