0
$\begingroup$

For example: Prove that (something)⊨(another thing)

Is it the same as "Prove that (something)⊢(another thing)"?

The single turnstile symbol always appears during sample proofs in my lecture notes. Yet my homework question suddenly got the double turnstile symbol, am I supposed to take it as a single turnstile symbol and do syntactical proving using natural deduction? Thanks!

  • 2
    $\vDash$ usually refers to semantic entailment. In the presence of a soundness theorem, $P \vdash Q$ implies $P \vDash Q$.2012-09-02
  • 2
    The person in the best place to answer your question is the person who assigned the homework.2012-09-02
  • 1
    Possibly useful: [What is the difference between ⊢ and ⊨?](http://math.stackexchange.com/questions/148177/what-is-the-difference-between-and)2012-09-02

1 Answers 1