Turnstile

In mathematical logic and computer science the symbol has taken the name turnstile because of its resemblance to a typical turnstile if viewed from above. It is also referred to as tee and is often read as "yields" or "proves". The symbol was first used by Gottlob Frege in his 1879 book on logic, Begriffsschrift. In TeX, the turnstile symbol is obtained from the command \vdash. In Unicode, the turnstile symbol ⊢ is called right tack and is at cod... more

In mathematical logic and computer science the symbol has taken the name turnstile because of its resemblance to a typical turnstile if viewed from above. It is also referred to as tee and is often read as "yields" or "proves". The symbol was first used by Gottlob Frege in his 1879 book on logic, Begriffsschrift. In TeX, the turnstile symbol is obtained from the command \vdash. In Unicode, the turnstile symbol ⊢ is called right tack and is at code point U+22A2. On a typewriter, a turnstile can be composed from a vertical bar (|) and a dash (-). In LaTeX there is the turnstile package, which issues this sign in many ways, and is capable of putting labels below or above it, in the correct places. The article A Tool for Logicians is a tutorial on using this package. The turnstile is a binary relation. It has several different meanings in different contexts: less