1. 31 Oct, 2017 1 commit
  2. 30 Oct, 2017 3 commits
    • Robbert Krebbers's avatar
      Drop positivity axiom of the BI canonical structure. · f2eaf912
      Robbert Krebbers authored
      The absence of this axiom has two consequences:
      
      - We no longer have `■ (P ∗ Q) ⊢ ■ P ∗ ■ Q` and `□ (P ∗ Q) ⊢ □ P ∗ □ Q`,
        and as a result, separating conjunctions in the unrestricted/persistent
        context cannot be eliminated.
      - When having `(P -∗ ⬕ Q) ∗ P`, we do not get `⬕ Q ∗ P`. In the proof
        mode this means when having:
      
          H1 : P -∗ ⬕ Q
          H2 : P
      
        We cannot say `iDestruct ("H1" with "H2") as "#H1"` and keep `H2`.
      
      However, there is now a type class `PositiveBI PROP`, and when there is an
      instance of this type class, one gets the above reasoning principle back.
      
      TODO: Can we describe positivity of individual propositions instead of the
      whole BI? That way, we would get the above reasoning principles even when
      the BI is not positive, but the propositions involved are.
      f2eaf912
    • Robbert Krebbers's avatar
      Define `Persistent P` as `P ⊢ □ P` instead of `□ P ⊣⊢ P`. · 96501a4f
      Robbert Krebbers authored
      Otherwise, ownership of cores in our ordered RA model will not be persistent.
      96501a4f
    • Robbert Krebbers's avatar
      Generalize proofmode. · 52c3006d
      Robbert Krebbers authored
      52c3006d