thys/Paper/Paper.thy
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   945   correctness proof of the POSIX value algorithm. Frisch and Cardelli
   945   correctness proof of the POSIX value algorithm. Frisch and Cardelli
   946   introduced an ordering, written $\greedy$, for values and they show that
   946   introduced an ordering, written $\greedy$, for values and they show that
   947   their greedy matching algorithm always produces a maximal element
   947   their greedy matching algorithm always produces a maximal element
   948   according to this ordering (from all possible solutions). The only
   948   according to this ordering (from all possible solutions). The only
   949   difference between their greedy ordering and the ``ordering'' by Sulzmann
   949   difference between their greedy ordering and the ``ordering'' by Sulzmann
   950   and Lu is that GREEDY always prefers a $Left$-value over a $Right-value$.
   950   and Lu is that GREEDY always prefers a $Left$-value over a $Right$-value.
   951   What is interesting for our purposes is that the properties reflexivity,
   951   What is interesting for our purposes is that the properties reflexivity,
   952   totality and transitivity for this GREEDY ordering can be proved
   952   totality and transitivity for this GREEDY ordering can be proved
   953   relatively easily by induction.
   953   relatively easily by induction.
   954 
   954 
   955   These properties of GREEDY, however, do not transfer to POSIX by 
   955   These properties of GREEDY, however, do not transfer to POSIX by