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language Essence 1.3
$ prob003: quasigroup existence QG4
$ http://www.csplib.org/Problems/prob003

given n : int(1..100)
letting g be domain int (0..n-1)

find quasigroup : function(total) tuple(g,g) --> g

such that
  $ Latin square-ness
  forAll v : g . injective(restrict(quasigroup,`tuple(int(v),g)`)),
  forAll v : g . injective(restrict(quasigroup,`tuple(g,int(v))`)),

  $ qg4 ((b*a)*(a*b))=a
  forAll a,b : g . quasigroup((quasigroup((b,a)),quasigroup((a,b)))) = a