Definitions
1.NounThe state or quality of being sound.
2.NounThe result or product of being sound.
3.NounThe property (of an argument) of not only being valid, but also of having true premises.
4.NounThe property of a logical theory that whenever a wff is a theorem then it must also be valid. Symbolically, letting T represent a theory within logic L, this can be represented as the property that whenever
T
⊢
φ
{\displaystyle T\vdash \varphi }
is true, then
T
⊨
φ
{\displaystyle T\vDash \varphi }
must also be true, for any wff φ of logic L.