module chap8
imports signatures/-

rules

   SwapWithPat = ?Or(e1,e2); !Or(e2,e1)
   SwapAnon = (Or(e1,e2) -> Or(e2,e1))
   NoSwapTwice = (Or(e1,e2) -> Or(e2,e1)); (Or(e1,e2) -> Or(e2,e1))
   OkSwapTwice =
     {e3,e4 : (Or(e3,e4) -> Or(e4,e3))}; {e3,e4 : (Or(e3,e4) -> Or(e4,e3))}
   TermWrap = !Or(<id>, Not(<id>))
   TermProj = ?Or(_, Not(<id>))