User Acceptance Test (UAT) is a testing of the software by the User or Client, known as beta or end-user testing. It is a testing to determine whether or not it is acceptable. This is the final test done after the functional, system and regression tests have been carried out.
Lean was developed at Microsoft Research as an open source theorem provider and its standard library at Carnegie Mellon University. The Lean Theorem Prover is designed to bridging the gap between theorem proofs.
Software Development Life Cycle (SDLC) is a software industry process that designs, develops and tests high quality software, which aims at producing software of high quality which fulfills or surpasses customer expectations and completes time frames and costing estimates.