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| -rw-r--r-- | theories/Logic/ClassicalFacts.v | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/theories/Logic/ClassicalFacts.v b/theories/Logic/ClassicalFacts.v index 6bd4cdcf19..6cff067a3b 100644 --- a/theories/Logic/ClassicalFacts.v +++ b/theories/Logic/ClassicalFacts.v @@ -211,9 +211,12 @@ End Proof_irrelevance_CIC. (i.e. propositional extensionality + excluded middle) without dependent case analysis ? - Conjecture: it seems possible to build a model of CC interpreting - all non-empty types by the set of all lambda-terms. Such a model would - satisfy propositional degeneracy without satisfying proof-irrelevance - (nor dependent case analysis). This would imply that the previous - results cannot be refined. + Berardi [Berardi] built a model of CC interpreting inhabited + types by the set of all untyped lambda-terms. This model satisfies + propositional degeneracy without satisfying proof-irrelevance (nor + dependent case analysis). This implies that the previous results + cannot be refined. + + [Berardi] Stefano Berardi, "Type dependence and constructive mathematics", + Ph. D. thesis, Dipartimento Matematica, Università di Torino, 1990. *) |