U+22AF "⊯" Negated Double Vertical Bar Double Right Turnstile Unicode Character

U+22AF "⊯" Negated Double Vertical Bar Double Right Turnstile is a logical and mathematical symbol used primarily in formal logic, model theory, and metalogic to denote that a certain proposition or formula is not a logical consequence of a given set of premises under a specific interpretation or model. It visually combines a double vertical bar and a double right turnstile with a negation slash through the middle, effectively expressing the negation of the double turnstile relation. In practice, this symbol asserts that the premises do not satisfy or entail the conclusion in the semantic or model-theoretic sense, making it a critical tool for distinguishing between valid and invalid inferences in formal systems.