Double turnstile

In logic, the symbol ⊨, ⊧ or is called the double turnstile. It is often read as "entails", "models", "is a semantic consequence of" or "is stronger than".[1] It is closely related to the turnstile symbol , which has a single bar across the middle, and which denotes syntactic consequence (in contrast to semantic).

  1. ^ Nederpelt, Rob (2004). "Chapter 7: Strengthening and weakening". Logical Reasoning: A First Course (3rd revised ed.). King's College Publications. p. 62. ISBN 0-9543006-7-X.

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