University of Leicester

computer science

Publications of Fer-Jan de Vries

Refereed Publications

  1. A. Kurz, D. Petrisan, P. Severi and F.J. de Vries.
    An Alpha-Corecursion Principle for the Infinitary Lambda Calculus
    to appear in proceedings of CMCS 2012: the 11th International Workshop on Coalgebraic Methods in Computer Science. 31 March - 1 April 2012, Tallinn, Estonia.
    pdf

    Abstract Gabbay and Pitts proved that lambda-terms up to alpha-equivalence constitute an initial algebra for a certain endofunctor on the category of nominal sets. We show that the terms of the infinitary lambda-calculus form the final coalgebra for the same functor. This allows us to give a corecursion principle for alpha-equivalence classes of finite and infinite terms. As an application, we give corecursive definitions of substitution and of infinite normal forms (Bohm, Levy-Longo and Berarducci trees).

  2. P. Severi and F.J. de Vries.
    Weakening the Axiom of Overlap in Infinitary Lambda Calculus
    in proceedings of RTA2011: the 22nd International Conference on Rewriting Techniques and Applications. Editor Manfred Schmidt-Schauß. Novi Sad. May 30 - June 1, 2011. Leibniz International Proceedings in Informatics (LIPIcs) volume 10. Pages 313--328.
    pdf

    Abstract In this paper we present a set of necessary and sufficient conditions on a set of lambda terms to serve as the set of meaningless terms in an infinitary bottom extension of lambda calculus. So far only a set of sufficient conditions was known for choosing a suitable set of meaningless terms to make this construction produce confluent extensions. The conditions covered the three main known examples of sets of meaningless terms. However, the much later construction of many more examples of sets of meaningless terms satisfying the sufficient conditions renewed the interest in the necessity question and led us to reconsider the old conditions. The key idea in this paper is an alternative solution for solving the overlap between beta reduction and bottom reduction. This allows us to reformulate the Axiom of Overlap, which now determines together with the other conditions a larger class of sets of meaningless terms. We show that the reformulated conditions are not only sufficient but also necessary for obtaining a confluent and normalizing infinitary lambda beta bottom calculus. As an interesting consequence of the necessity proof we obtain for infinitary lambda calculus with beta and bot reduction that confluence implies normalization.

  3. P. Severi and F.J. de Vries.
    Decomposing the Lattice of Meaningless Sets in the Infinitary Lambda Calculus
    in proceedings of WoLLIC 2011, Logic, Language, Information and Computation - 18th International Workshop, Philadelphia, PA, USA, May 18-20, 2011. Editors Lev D. Beklemishev and Ruy de Queiroz. SLNAI 6642, pages 210-227, 2011.
    pdf

    Abstract The notion of a meaningless set has been defined for infinitary lambda calculus axiomatically. Standard examples of meaningless sets are sets of terms that have no head normal form, the set of terms without weak head normal form and the set of rootactive terms. The collection of meaningless sets is a lattice. In this paper, we study the way this lattices decompose as union of more elementary key intervals. We also analyse the distribution of the sets of meaningless terms in the lattice by selecting some sets as key vertices and study the cardinality in the intervals between key vertices. As an application, we prove that the lattice of meaningless sets is neither distributive nor modular. Interest- ingly, the example translates into a counterexample that the lattice of lambda theories is not modular.

  4. J.R. Kennaway, P. Severi, M.R. Sleep, and F.J. de Vries.
    Infinite rewriting: from syntax to semantics,
    in proceedings of Processes, Terms and Cycles: Steps on the Road to Infinity: Essays dedicated to Jan Willem Klop on the Occasion of His 60th Birthday, editors: A. Middeldorp, V. van Oostrom, F. van Raamsdonk and R. de Vrijer. SLNCS 3838, pages 148-172, 2005.
    pdf

  5. P. Severi and F.J. de Vries.
    Separability of infinite lambda terms
    in proceedings of the LCTTNL Workshop: The second workshop on Lambda Calculus, Type Theory and Natural Language, King's College London, 12th September 2005. Page 1-12.
    pdf

    Abstract Infinite lambda calculi extend finite lambda calculus with infinite terms and transfinite reduction. In this paper we extend some classical results of finite lambda calculus to infinite terms. First we extend to infinite terms is B\"ohm Theorem which states the separability of two finite $\beta \eta$-normal forms. Next we extend to infinite terms is the equivalence of the prefix relation up to infinite eta expansions and the contextual preorder that observes head normal forms. Finally we prove that the theory given by equality of $\infty \eta$-B\"ohm trees is the largest theory induced by the confluent and normalising infinitary lambda calculi extending the calculus of B\"ohm trees.

  6. P. Severi and F.J. de Vries.
    Order Structures on Böhm-like Models
    Conference paper in Luke Ong, editor, Computer Science Logic: 19th International Workshop, CSL 2005, 14th Annual Conference of the EACSL, Oxford, UK. August 22-25, 2005. (Lecture Notes in Computer Science 3634), Springer-Verlag. Page 103-116. 2005.
    dvi, ps and pdf

    Abstract We are interested in the question whether the models induced by the infinitary lambda calculus are orderable, that is whether they have a partial order with a least element making the context operators monotone. The first natural candidate is the prefix relation: a prefix of a term is obtained by replacing some subterms by $\bot$. We prove that six models induced by the infinitary lambda calculus (which includes Böhm and Lévy-Longo trees) are orderable by the prefix relation. The following two orders we consider are the compositions of the prefix relation with either transfinite $\eta$-reduction or transfinite $\eta$-expansion. We prove that these orders make the context operators of the $\eta$-Böhm trees and the $\infty \eta$-Böhm trees monotone. The model of Berarducci trees is not monotone with respect to the prefix relation. However, somewhat unexpectedly, we found that the Berarducci trees are orderable by a new order related to the prefix relation in which subterms are not replaced by $\bot$ but by a lambda term $\Ogreterm$ called the ogre which devours all its inputs. The proof of this uses simulation and coinduction. Finally, we show that there are $2^c$ unorderable models induced by the infinitary lambda calculus where $c$ is the cardinality of the continuum.

  7. P. Severi and F.J. de Vries.
    Continuity and Discontinuity in Lambda Calculus
    Conference paper in Pawel Urzyczyn, editor, Typed Lambda Calculus and Applications, Proceedings of the 7th International Conference, TLCA 2005, Nara Japan, April 21-23 2005. (Lecture Notes in Computer Science 3461), Springer-Verlag. Page 369-385. 2005.
    dvi, ps and pdf

    Abstract This paper studies continuity of the normal form and the context operators as functions in the infinitary lambda calculus. We consider the Scott topology on the cpo of the finite and infinite terms with the prefix relation. We prove that the only continuous parametric trees are Böhm and Lévy-Longo trees. We also prove a general statement: if the normal form function is continuous then so is the model induced by the normal form; as well as the converse for parametric trees. This allows us to deduce that the only continuous models induced by the parametric trees are the ones of Böhm and Lévy-Longo trees. As a first application, we prove that there is an injective embedding from the infinitary lambda calculus of the infinite eta-Böhm trees in D-infinity. As a second application, we study the relation between the Scott topology on the prefix relation and the tree topologies. This allows us to prove that the only parametric tree topologies in which all context operators are continuous and the approximation property holds are the ones of Böhm and Lévy-Longo. As a third application, we give an explicit characterisation of the open sets of the Böhm and Lévy-Longo tree topologies.

  8. J.R. Kennaway and F.J. de Vries.
    Infinitary Rewriting.
    Chapter 12 in Terese, editor, Term Rewriting Systems (Cambridge Tracts in Theoretical Computer Science 55), Cambridge University Press. Page 668-711. 2003. Erratum.
    dvi, ps and pdf

    Abstract In this chapter we will give the basic definitions and properties of infinite terms and infinite reduction sequences, for both term rewrite systems and the lambda calculus. We will then study confluence properties in orthogonal systems, which turns out to be significantly more complicated than in the finitary case. In general, these systems are only confluent up to an identification of a certain class of terms. The breakdown of confluence leads us to consider the concept of a meaningless term, which further suggests a link with the lambda-calculus concept of Böhm reduction, and to denotational semantics for TRSs.

  9. M. Dezani-Ciancaglini, P. Severi and F.J. de Vries.
    Infinitary Lambda Calculus and Discrimination of Berarducci trees.
    Theoretical Computer Science 298(2):275 - 302, 2003.
    dvi, ps and pdf

    Abstract We propose an extension of lambda calculus for which the Berarducci trees equality coincides with observational equivalence, when we observe rootstable or rootactive behavior of terms. In one direction the proof is an adaptation of the classical Böhm out technique. In the other direction the proof is based on confluence for strongly converging reductions in this extension.

  10. P. Severi and F.J. de Vries.
    An Extensional Böhm Model.
    Conference paper in Sophie Tison, editor, Rewiting Techniques and Applications, Proceedings of the 13th International Conference, RTA 2002, Copenhagen Denmark, July 2002. (Lecture Notes in Computer Science 2378), Springer-Verlag. Page 159-173. 2002.
    dvi, ps and pdf (15 pages)

    Abstract We show the existence of an infinitary confluent and normalising extension of the finite extensional lambda calculus with beta and eta. Besides infinite beta reductions also infinite eta reductions are possible in this extension, and terms without head normal form can be reduced to bottom. As corollaries we obtain a simple, syntax based construction of an extensional Böhm model of the finite lambda calculus; and a simple, syntax based proof that two lambda terms have the same semantics in this model if and only if they have the same eta-Böhm tree if and only if they are observationally equivalent wrt to beta normal forms. The confluence proof reduces confluence of beta bottom and eta via infinitary commutation and postponement arguments to confluence of beta and bottom and confluence of eta. We give counterexamples against confluence of similar extensions based on the identification of the terms without weak head normal form and the terms without top normal form (rootactive terms) respectively.

  11. S. van Bakel, F. Barbanera, M. Dezani-Ciancaglini, F.J. de Vries.
    Intersection Types for Lambda Trees.
    Theoretical Computer Science 272(1-2): 3-40, 2002.
    ps and pdf (42 pages)

    Abstract We introduce a type assignment system which is parametric with respect to five families of trees obtained by evaluating lambda terms (Böhm trees, Lévy-Longo trees, etc.). then we prove, in an (almost ) uniform way that each type assignment system fully describes the observational equivalences induced by the corresponding tree representation of lambda trees. More precisely, for each family of trees, two lambda terms have the same tree if and only if they get assigned the same types in the corresponding type assignment system.

  12. M. Dezani-Ciancaglini, P. Severi and F.J. de Vries.
    Böhm's theorem for Berarducci trees.
    In Proceedings CATS 2000 Computing: the Australasian Theory Symposium, Canberra, Australia, February 1-2, 2000. Electronic Notes in Theoretical Computer Science, volume 31, 24 pages, 2000.
    dvi (24 pages)

  13. J.R. Kennaway, V. van Oostrom, F.J. de Vries.
    Meaningless terms in rewriting.
    Journal of Logic and Functional Programming. The MIT Press. Article 1, 35 pages. Volume 1999.
    dvi, ps and pdf (35 pages)

    Abstract We present an axiomatic approach to the concept of meaninglessness in finite and transfinite term rewriting and lambda calculus. We justify our axioms in several ways. They can be intuitively justified from the viewpoint of rewriting as computation. They are shown to imply important properties of meaninglessness: genericity of the class of meaningless terms, confluence modulo equality of meaningless terms, the consistency of equating all meaningless terms, and the construction of Böhm trees and models of rewrite systems. Finally, we show that they can be easily verified for many existing notions of meaninglessness, and easily refuted for some notions that are known not to be good characterisations of meaninglessness.

  14. F. Barbanera, M. Dezani-Ciancaglini, F.J. de Vries.
    Types for trees.
    In Proceedings IFIP Working Conference on Programming Concepts and Methods (PROCOMET '98), Shelter Island, New York, Chapman and Hall, pages 6-29, 1998.

  15. J.R. Kennaway, J.W. Klop, M.R. Sleep, F.J. de Vries.
    Infinitary lambda calculus.
    Theoretical Computer Science 175(1):93-125, 1997.
    dvi, ps and pdf (38 pages)

    Abstract In a previous paper we have established the theory of transfinite reduction for orthogonal term rewriting systems. In this paper we perform the same task for the lambda calculus. From the viewpoint of infinitary rewriting, the Böhm model of the lambda calculus can be seen as an infinitary term model. In contrast to term rewriting, there are several different possible notions of infinite term, which give rise to different Böhm-like models, which embody different notions of lazy or eager computation.

  16. F.J. de Vries.
    Böhm trees, bisimulations and observations in lambda calculus.
    In Proceedings of the Second Fuji International Workshop on Functional and Logic Programming Workshop Shonan Village Center, Japan 1-4 November 1996. Editors: T. Ida, A. Ohori and M. Takeichi. World Scientific, Singapore, pages 230-245, 1997.

  17. J.R. Kennaway, J.W. Klop, M.R. Sleep and F.J. de Vries.
    Comparing curried and uncurried rewrite systems.
    Journal of Symbolic Computation, 21(1):15-39, 1996.
    dvi, ps and pdf (25 pages)

  18. J.R. Kennaway, V. van Oostrom, F.J. de Vries.
    Meaningless terms in rewriting.
    In Proceedings of the Fifth International Conference on Algebraic and Logic Programming Aachen (Germany), September 25-27, 1996. Series: Lecture Notes in Computer Science 1139, Springer-Verlag, pages 254-268, 1996.

  19. J.R. Kennaway, J.W. Klop, M.R. Sleep, F.J. de Vries.
    Infinite lambda calculus and Böhm models.
    In Proceedings Rewriting Techniques and Applications, Kaiserslautern, 1995. Series: Lecture Notes in Computer Science 914, Springer-Verlag, pages 257-270, 1995.

  20. J.R. Kennaway, J.W. Klop, M.R. Sleep, F.J. de Vries.
    From Finite to Infinite Lambda Calculi.
    Bulletin of the section of Logic, University of Lodz, Department of Logic (Special issue dedicated to the Workshop on Non-standard Logics and Logical Aspects of Computer Science, Kanazawa, Japan, Dec. 5-8. 1994, editor Hiroakira Ono), 24(1)13-20, 1995.
    pdf (8 pages)

    Abstract In a previous paper we have established the theory of transfinite reduction for orthogonal term rewriting systems. In this paper we perform the same task for the lambda calculus. This results in several new Bohm models of the lambda calculus and new unifying descriptions of existing models.

  21. D.J.N van Eijck and F.J. de Vries.
    Reasoning about Update Logic.
    Journal of Philosophical Logic, 24(1):19-47, 1995.
    dvi, ps and pdf (19 pages)

  22. E. Horita and F.J. de Vries. A fully abstract denotational model for communicating processes with label-passing. In Proceedings of Concurrency Theory and Its Application, RIMS Kokyuroku 902, page 26-48, 1995.

  23. J.R. Kennaway, J.W. Klop, M.R. Sleep and F.J. de Vries.
    Transfinite Reductions in Orthogonal Term Rewriting Systems.
    Information and Computation, 119(1):18-38, 1995.
    ps and pdf (36 pages)

    Abstract We define the notion of transfinite term rewriting: rewriting in which terms may be infinitely large and rewrite sequences may be of any ordinal length. For orthogonal rewrite systems, some fundamental properties known in the finite case are extended to the transfinite case. Among these are the Parallel Moves lemma and the Unique Normal Form property. The transfinite Church-Rosser property fails in general, even for orthogonal systems, including such well-known systems as Combinatory Logic. Syntactic characterisations are given of some classes of orthogonal TRSs which do satisfy the transfinite Church-Rosser property. We also prove a weakening of the transfinite Church-Rosser property for all orthogonal systems, in which the property is only required to hold up to a certain equivalence relation on terms. Finally, we extend the theory of needed reduction from the finite to the transfinite case. The reduction strategy of needed reduction is normalising in the finite case, but not in the transfinite case. To obtain a normalising strategy, it is necessary and sufficient to add a requirement of fairness. Parallel outermost reduction is such a strategy.

  24. Z. Ariola, J.R. Kennaway, J.W. Klop, M.R. Sleep and F.J. de Vries.
    On defining the undefined.
    In the proceedings: TACS'94 (Theoretical Aspects of Computer Software) International conference in Sendai. Series: Lecture Notes in Computer Science 789, Springer-Verlag, pages 543-554, 1994.

  25. J.R. Kennaway, J.W. Klop, M.R. Sleep and F.J. de Vries.
    On the Adequacy of Graph Rewriting for Simulating Term Rewriting.
    Transactions on Programming Languages and Systems, 16(3):493-523, 1994.
    ps (29 pages)

  26. F.J. de Vries and J. Yamada.
    On termination of rewriting with real numbers.
    In proceedings: Functional Programming II, JSSST'94. Editor Masato Takeichi. Series: Lecture Notes on Software Gaku 10. Publisher: Kindai-kagaku-sya, Tokyo. Pages 233-247, 1994.
    ps (18 pages), pdf (18 pages) and Addendum (Oct 13, 2004)

  27. J.R. Kennaway, J.W. Klop, M.R. Sleep and F.J. de Vries.
    An Introduction to Term Graph Rewriting.
    Chapter 1 in M.R. Sleep, M.J. Plasmeijer and M.C. van Eekelen, editors, Term Graph Rewriting: Theory and Practice, John Wiley ™Sons Ltd, pages 1-13, 1993.

  28. J.R. Kennaway, J.W. Klop, M.R. Sleep and F.J. de Vries.
    An infinitary Church-Rosser property for non-collapsing orthogonal term rewriting systems.
    Chapter 4 in M.R. Sleep, M.J. Plasmeijer and M.C. van Eekelen, editors, Term Graph Rewriting: Theory and Practice, John Wiley ™ Sons Ltd, pages 47-59, 1993.

  29. J.R. Kennaway, J.W. Klop, M.R. Sleep and F.J. de Vries.
    Event Structures and Orthogonal Term Graph Rewriting.
    Chapter 11 in M.R. Sleep, M.J. Plasmeijer and M.C. van Eekelen, editors, Term Graph Rewriting: Theory and Practice, John Wiley ™Sons Ltd, pages 141-155, 1993.

  30. J.R. Kennaway, J.W. Klop, M.R. Sleep and F.J. de Vries.
    On the adequacy of graph rewriting for simulating term rewriting.
    Chapter 12 in M.R. Sleep, M.J. Plasmeijer and M.C. van Eekelen, editors, Term Graph Rewriting: Theory and Practice, John Wiley ™ Sons Ltd, pages 157-169, 1993.

  31. D.J.N van Eijck and F.J. de Vries.
    Dynamic interpretation and Hoare deduction.
    Journal of Logic, Language and Information, 1(1):1-44, 1992.
    dvi, ps and pdf (43 pages)

  32. D.J.N van Eijck and F.J. de Vries.
    Dynamic interpretation and Hoare deduction (Extended Abstract).
    In S. Moore and A.Z. Wyner, editors, Proceedings of Semantics and Linguistic Theory, SALT I, CLC Publications, Cornell University, Ithaca, N.Y., 10:65-85, 1991.

  33. J.R. Kennaway, J.W. Klop, M.R. Sleep and F.J. de Vries.
    Transfinite reductions in orthogonal term rewriting systems.
    In R.V. Book, editor, Proceedings of Rewriting Techniques and Applications, Como, Lecture Notes in computer Science 488, pages 1-12, 1991.
    pdf (12 pages)

  34. F.J. de Vries.
    Type theoretical topics in topos theory.
    PhD Thesis, University of Utrecht, April 13, 1989. Supervisor Prof D. van Dalen.

  35. D. van Dalen and F.J. de Vries.
    Intuitionistic Free Abelian Groups.
    Zeitschrift für Mathematischen Logik und Grundlagen der Mathematik, 34(1):3-12, 1988.

  36. F.J. de Vries.
    A functional program for the Fast Fourier Transform.
    SigmaPlan Notices, 23(1):67-74, 1988.


Unrefereed Publications

Papers in Unrefereed Proceedings

  1. J. Giesl, J.R, V. van Oostrom, F.J. de Vries. Strong convergence of term rewriting using strong dependency pairs. Extended abstract. In Proceedings of Termination Workshop, Schloss Dagstuhl, 1999.
    pdf (2 pages plus erratum)

  2. F.J. de Vries. Projection spaces and recursive domain equations. Information Processing Society of Japan SIG Notes. 95(114):37-38, 1995 .

  3. J.R. Kennaway, J.W. Klop, M.R. Sleep and F.J. de Vries. From finite lambda calculus to infinite lambda calculi (abstract) Information Processing Society of Japan, SIG Notes 94-PRG-19-6:43-50, 1994.

  4. J.R. Kennaway, J.W. Klop, M.R. Sleep and F.J. de Vries. On comparing curried and uncurried rewrite systems. In H.P. Barendregt, M. Bezem and J.W. Klop, editors, Festschrift dedicated to the sixtieth anniversary of Dirk van Dalen, Quaestiones Infinitae, Logic Series, Department of Philosophy, University of Utrecht, pages 57-78, 1993.

Reports

  1. P. Severi and F.J. de Vries.
    A lambda calculus for D-infinity.
    Presented at the Workshop at Domain Theory held at the honour of Dana Scott's 70th birthday.
    Technical Report tr-2002-29, University of Leicester, June 2002.
    dvi (10 pages), ps (10 pages)

    Abstract We define an extension of lambda calculus which is fully abstract for Scott's D-infinity models. We do so by constructing an infinitary lambda calculus which not only has the confluence property, but also is normalising: every term has its inf-eta-Böhm tree as unique normal form. The extension incorporates a strengthened form of eta-reduction besides infinite terms, infinite reductions and a bottom rule allowing to replace terms without head normal form by bottom. The new eta!-reduction is the key idea of this paper. It allows us to capture in a compact and natural way Barendregt's complex infinite eta-operation on Böhm trees. As a corollary we obtain a new congruence proof for Böhm tree equivalence modulo infinite eta-expansion.

  2. P. Severi and F.J. de Vries.
    An Extensional Böhm Model.
    In the Proceedings of RTA'02, Springer Lecture Notes in Computer Science 2378.
    Technical Report tr-2002-28, University of Leicester, June 2002.
    dvi (15 pages), ps (15 pages)

    Abstract We show the existence of an infinitary confluent and normalising extension of the finite extensional lambda calculus with beta and eta. Besides infinite beta reductions also infinite eta reductions are possible in this extension, and terms without head normal form can be reduced to bottom. As corollaries we obtain a simple, syntax based construction of an extensional Böhm model of the finite lambda calculus; and a simple, syntax based proof that two lambda terms have the same semantics in this model if and only if they have the same eta-Böhm tree if and only if they are observationally equivalent wrt to beta normal forms. The confluence proof reduces confluence of beta, bottom and eta via infinitary commutation and postponement arguments to confluence of beta and bottom and confluence of eta. We give counterexamples against confluence of similar extensions based on the identification of the terms without weak head normal form and the terms without top normal form (rootactive terms) respectively.

  3. S. Byun, J.R. Kennaway, V. van Oostrom, F.J. de Vries.
    Separability and translatability of sequential term rewrite systems into the lambda calculus.
    Technical Report tr-2001-16, University of Leicester, April 2001.
    dvi (35 pages), ps (35 pages)

    Abstract Orthogonal term rewrite systems do not currently have any semantics other than syntactically-based ones such as term models and event structures. For a functional language which combines lambda calculus with term rewriting, a semantics is most easily given by translating the rewrite rules into lambda calculus and then using well-understood semantics for the lambda calculus. We therefore study in this paper the question of which classes of TRSs do or do not have such translations. We demonstrate by construction that forward branching orthogonal term rewrite systems are translatable into the lambda calculus. The translation satisfies some strong properties concerning preservation of equality and of some inequalities. We prove that the forward branching systems are exactly the systems permitting such a translation which is, in a precise sense, uniform in the right-hand sides. Connections are drawn between translatability, sequentiality and separability properties. Simple syntactic proofs are given of the non-translatability of a class of TRSs, including Berry's F and several variants of it.

  4. J.R. Kennaway and F.J. de Vries.
    Infinitary Rewriting.
    Technical Report tr-2001-13, University of Leicester, March 2001.
    dvi (48 pages), ps (48 pages)

    Abstract In this chapter we will give the basic definitions and properties of infinite terms and infinite reduction sequences, for both term rewrite systems and the lambda calculus. We will then study confluence properties in orthogonal systems, which turns out to be significantly more complicated than in the finitary case. In general, these systems are only confluent up to an identification of a certain class of terms. The breakdown of confluence leads us to consider the concept of a meaningless term, which further suggests a link with the lambda-calculus concept of Böhm reduction, and to denotational semantics for TRSs.

  5. M. Dezani-Ciancaglini, P. Severi and F.J. de Vries.
    Infinitary Lambda Calculus and Discrimination.
    Technical Report tr-2001-06, University of Leicester, February 2001.
    dvi (33 pages), ps (33 pages)

    Abstract We propose an extension of lambda calculus for which the Berarducci trees equality coincides with observational equivalence, when we observe rootstable or rootactive behavior of terms. In one direction the proof is an adaptation of the classical Böhm out technique. In the other direction the proof is based on confluence for strongly converging reductions in this extension.

  6. J.R. Kennaway, V. van Oostrom, F.J. de Vries. Meaningless terms in rewriting, revised version. Technical Report: Utrecht Universiteit, Artificial Intelligence Preprint Series No: 003, May, 1999.

  7. F. Barbanera, M. Dezani-Ciancaglini, F.J. de Vries. Types for Trees. Technical Report: Dipartimento di Unformatica, Universita' di Torino, 1997.

  8. J.R. Kennaway, V. van Oostrom, F.J. de Vries. Meaningless terms in rewriting Technical Report: Vrije Universiteit, Amsterdam, IR-418, 23 pages, January, 1997.

  9. J.R. Kennaway, J.W. Klop, M.R. Sleep, F.J. de Vries. Infinite lambda calculus, Report CS-R9535, CWI, Amsterdam, 1995.

  10. E. Horita and F.J. de Vries. A fully abstract denotational model for communicating processes with label-passing. ECL Technical Report. NTT Kyoto, 1994.

  11. J.R. Kennaway, J.W. Klop, M.R. Sleep, F.J. de Vries. On comparing curried and uncurried rewrite systems. Revised version of Festschrift version. Report CS-R9350, CWI, Amsterdam, 1993.

  12. D.J.N. van Eijck and F.J. de Vries. Reasoning about Update Logic, (Completely revised version of report CS-R9155), Report CS-R9312, CWI, Amsterdam, 1993.

  13. Kennaway J.R., Klop J.W., Sleep M.R., Vries F.-J. de, Transfinite reductions in orthogonal term rewriting systems, Report SYS-C93-10, School of Information Systems, Univ. of East Anglia, Norwich, England. Revised version of 17.

  14. J.R. Kennaway, J.W. Klop, M.R. Sleep, F.J. de Vries. On the Adequacy of Graph Rewriting for Simulating Term Rewriting, Report CS9204, CWI, Amsterdam, 1992. Similar as 10.

  15. J.R. Kennaway, J.W. Klop, M.R. Sleep, F.J. de Vries. On the Adequacy of Graph Rewriting for Simulating Term Rewriting, Report IR-287, Vrije Universiteit Amsterdam.

  16. D.J.N. van Eijck and F.J. de Vries. A sound and complete calculus for Update Logic, report CS-R9155, CWI, Amsterdam, 1991.

  17. J.R. Kennaway, J.W. Klop, M.R. Sleep, F.J. de Vries. Event structures and orthogonal term graph rewriting, in M.J. Plasmeijer and M.R. Sleep, editors, Sema Graph '91, Part II, Technical Report 91-25, Department of Informatics, University of Nijmegen, 1991.

  18. J.R. Kennaway, J.W. Klop, M.R. Sleep, F.J. de Vries. Finite orthogonal graph rewriting is adequate for rational orthogonal term rewriting, in M.J. Plasmeijer and M.R. Sleep, editors, Sema Graph '91, Part I, Technical Report 91-25, Department of Informatics, University of Nijmegen, 1991.

  19. D.J.N. van Eijck and F.J. de Vries. Dynamic interpretation and Hoare deduction, report CS-R9115, CWI, Amsterdam, 1991.

  20. J.R. Kennaway, J.W. Klop, M.R. Sleep, F.J. de Vries. An infinitary Church-Rosser property for non-collapsing orthogonal term rewriting systems, report CS-R9043, CWI, Amsterdam, 1990.

  21. J.R. Kennaway, J.W. Klop, M.R. Sleep, F.J. de Vries. Transfinite reductions in orthogonal term rewriting systems (Extended abstract), report CS-R9042, CWI, Amsterdam, 1990.

  22. J.R. Kennaway, J.W. Klop, M.R. Sleep, F.J. de Vries. Transfinite reductions in orthogonal term rewriting systems (Full version) , report CS-R9041, CWI, Amsterdam, 1990. .
    pdf (47 pages)

  23. A. Ponse and F.J. de Vries. Strong completeness for Hoare Logics of Recursive Processes: an infinitary approach, report CS-R8957, CWI, Amsterdam, 1989.

  24. F.J. de Vries. Applications of constructive logic to sheaf constructions in toposes, Logic Group Preprint Series No. 25, Department of Philosophy, University of Utrecht, October 1987.

  25. F.J. de Vries. A functional program for Gaussian elimination, Logic Group Preprint Series No. 23, Department of Philosophy, University of Utrecht. September 1987.

  26. F.J. de Vries. A functional program for the Fast Fourier Transform, Logic Group Preprint Series No. 19, Department of Philosophy, University of Utrecht, April 1987.

  27. D. van Dalen and F.J. de Vries. Intuitionistic Free Abelian Groups, Logic Group Preprint Series No. 7, Department of Philosophy, University of Utrecht, April 1986.

  28. F.J. de Vries. Type theory with a geometric modality and extensions of the reals, Preprint 340, Mathematical Institute, University of Utrecht, June 1984.

Book reviews

  1. Review of Algebra in a localic topos, with applications to ring theory by F.Borceux and G. van den Bossche, Nov 1985, Mededelingen van het Wiskundig Genootschap.

  2. Review of Antimorphic action by W.H. Cornish, 1988, Mededelingen van het Wiskundig Genootschap.

  3. Review of Graph-grammars and their application to computer science by H.Ehrig, e.a. (eds), 1990, Informatie.

  4. Review of Cartesian closed categories of domains by A. Jung, 1990, Mededelingen van het Wiskundig Genootschap.

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Author: F.J. de Vries (fdv1 at mcs.le.ac.uk).
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