\nvdashThe symbol \nvdash is used in logic to denote that a particular statement or formula is not provable or does not entail another statement. It is the negation of the \vdash symbol, which represents provability or derivation in formal systems.
Statement A does not entail statement B.
A \nvdash BThe set of statements \Gamma does not prove the statement \phi.
\Gamma \nvdash \phiThe predicate P(x) does not entail the predicate Q(x).
P(x) \nvdash Q(x)