Soundness
Soundness is the formal property in Systems Engineering/Computing Science to measure or represent the quality of a statement being provably true.
The notion of Soundness is explicitly investigated in the works of Abstract Interpretation, where statements in computable source code can be estimated in terms of their Soundness. Abstract Interpretation often study a system specification in a setting of the following trio: Soundness, Precision, and Terminability.
{{#ev:youtube|https://www.youtube.com/watch?v=9Utsppn-M_I%7C%7C%7C%7C%7C}}
In the video shown above, Soundness is defined as a proof, which attain the quality of reaching tautology. The notion of tautology can be explained in a simpler term. If one can keep all the logical statements in the proof process to be true, then, it is a tautology.