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2. Kim Bruce, Roberto Di Cosmo, and Giuseppe Longo. Provable isomorphisms of types. Technical Report 90–14, LIENS — Ecole Normale Supérieure, 1990. To appear in Proc. of Symposium on Symbolic Computation, ETH, Zurich, March 1990: MSCS.
3. Pierre-Louis Curien and Roberto Di Cosmo. A confluent reduction system for the λ-calculus with surjective pairing and terminal object. Technical Report, LIENS — Ecole Normale Supérieure, 1991. To appear.
4. Pierre-Louis Curien and Giorgio Ghelli. Subtyping and extensionality: decidability of βηtop≤ on F≤. 1990. Draft.
5. Roberto Di Cosmo. Invertibility of terms and valid isomorphisms. A proof theoretic study on second order λ-calculus with surjective pairing and terminal object. Technical Report, LIENS — Ecole Normale Supérieure, 1991. To appear.