\nvDashThe symbol \nvDash represents the negation of the semantic entailment or satisfaction relation. In logic, it is used to denote that a particular statement or formula does not semantically entail another, or that a structure does not satisfy a given formula.
Statement A does not semantically entail statement B.
A \nvDash BStructure M does not satisfy the formula \phi.
M \nvDash \phiThe set of formulas \Gamma does not entail the set of formulas \Delta.
\Gamma \nvDash \Delta