What is the type theory judgement symbol? In type theory judgements are often presented with the following syntax:



My question is what is that symbol in the middle called? All the papers I've found seem to use an image rather than a unicode character so I can't look it up. I've also not found any type-theory reference which says what that symbol is (they explain what it means however).

So what character is that symbol and what is its proper name?
It's called a "turnstile". See the Wikipedia article.