1 research outputs found
Epistemic systems and Flagg and Friedman's translation
In 1986, Flagg and Friedman \cite{ff} gave an elegant alternative proof of
the faithfulness of G\"{o}del (or Rasiowa-Sikorski) translation
of Heyting arithmetic to Shapiro's epistemic arithmetic . In
\S 2, we shall prove the faithfulness of without using
stability, by introducing another translation from an epistemic system to
corresponding intuitionistic system which we shall call \it the modified
Rasiowa-Sikorski translation\rm . That is, this introduction of the new
translation simplifies the original Flagg and Friedman's proof. In \S 3, we
shall give some applications of the modified one for the disjunction property
() and the numerical existence property () of
Heyting arithmetic. In \S 4, we shall show that epistemic Markov's rule
in is proved via . So and are equivalent. In \S 5, we
shall give some relations among the translations treated in the previous
sections. In \S 6, we shall give an alternative proof of Glivenko's theorem. In
\S 7, we shall propose several(modal-)epistemic versions of Markov's rule for
Horsten's modal-epistemic arithmetic . And, as in \S 4, we shall study
some meta-implications among those versions of Markov's rules in and
one in . Friedman and Sheard gave a modal analogue (i.e.
Theorem in \cite{fs}) of Friedman's theorem (i.e. Theorem 1 in
\cite {friedman}): \it Any recursively enumerable extension of which
has also has \rm . In \S 8, we shall give a proof
of our \it Fundamental Conjecture \rm proposed in Inou\'{e}
\cite{ino90a} as follows: This is a new type of proofs. In \S 9, I
shall give discussions.Comment: 33 page