Embeddings into the Medvedev and Muchnik lattices of Π1 classes

نویسندگان

  • Stephen Binns
  • Stephen G. Simpson
چکیده

Let Pw and PM be the countable distributive lattices of Muchnik and Medvedev degrees of non-empty Π1 subsets of 2 , under Muchnik and Medvedev reducibility, respectively. We show that all countable distributive lattices are lattice-embeddable below any non-zero element of Pw. We show that many countable distributive lattices are lattice-embeddable below any non-zero element of PM .

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تاریخ انتشار 2004