Publications

Books

C.A. Middelburg. Logic and Specification. Computer Science: Research and Practice, Vol. 1, Chapman & Hall, 1993.   ISBN: 0-412-48680-6.

L.M.G. Feijs, H.B.M. Jonkers and C.A. Middelburg. Notations for Software Design. FACIT Series, Springer-Verlag, 1994.   DOI: 10.1007/978-1-4471-2107-7.

J.C.M. Baeten and C.A. Middelburg. Process Algebra with Timing. EATCS Monographs Series, Springer-Verlag, 2002.   DOI: 10.1007/978-3-662-04995-2.

J.A. Bergstra and C.A. Middelburg. Instruction Sequences for Computer Science. Atlantis Studies in Computing, Vol. 2, Atlantis Press, 2012.   DOI: 10.2991/978-94-91216-65-7.

Handbook chapters

J.C.M. Baeten and C.A. Middelburg. Process algebra with timing: real time and discrete time. In J.A. Bergstra, A. Ponse and S.A. Smolka, editors, Handbook of Process Algebra, Chapter 10, Elsevier, 2001.   DOI: 10.1016/B978-044482830-9/50028-X.

J.A. Bergstra, C.A. Middelburg and Y.S. Usenko. Discrete time process algebra and the semantics of SDL. In J.A. Bergstra, A. Ponse and S.A. Smolka, editors, Handbook of Process Algebra, Chapter 18, Elsevier, 2001.   DOI: 10.1016/B978-044482830-9/50036-9.

Journal papers

C.A. Middelburg. VVSL: A language for structured VDM specifications. Formal Aspects of Computing, 1(1):115--135, 1989.   DOI: 10.1007/BF01887200.

C.A. Middelburg. Specification of interfering programs based on inter-conditions. Software Engineering Journal, 7(3), 205--217, 1992.   DOI: 10.1049/sej.1992.0022.

C.A. Middelburg. Modular structuring of VDM specifications in VVSL. Formal Aspects of Computing, 4(1):13--47, 1992.   DOI: 10.1007/BF01214955.

C.B. Jones and C.A. Middelburg. A typed logic of partial functions reconstructed classically. Acta Informatica, 31(5):399--430, 1994.   DOI: 10.1007/BF01178666.

J.A. Bergstra, W.J.Fokkink and C.A. Middelburg. Algebra of timed frames. International Journal of Computer Mathematics, 61:227--255, 1996.   DOI: 10.1080/00207169608804514.

J.A. Bergstra, C.A. Middelburg and Gh. Stefanescu. Network algebra for asynchronous dataflow. International Journal of Computer Mathematics, 65:57--88, 1997.   DOI: 10.1080/00207169708804599.

C.A. Middelburg. Truth of duration calculus formulae in timed frames. Fundamenta Informaticae, 36(2/3):235--263, 1998.   DOI: 10.3233/FI-1998-36236.

C.A. Middelburg. Variable binding operators in transition system specifications. Journal of Logic and Algebraic Programming, 47(1):15--45, 2001.   DOI: 10.1016/S1567-8326(00)00003-5.

J.C.M. Baeten and C.A. Middelburg. Real time process algebra with time-dependent conditions. Journal of Logic and Algebraic Programming, 48(1):1--37, 2001.   DOI: 10.1016/S1567-8326(01)00004-2.

C.A. Middelburg. Process algebra with nonstandard timing. Fundamenta Informaticae, 53(1):55--77, 2002.   Electronic version.

C.A. Middelburg. Revisiting timing in process algebra. Journal of Logic and Algebraic Programming, 54(1/2):109--127, 2003.   DOI: 10.1016/S1567-8326(02)00029-2.

C.A. Middelburg. An alternative formulation of operational conservativity with binding terms. Journal of Logic and Algebraic Programming, 55(1/2):1--19, 2003.   DOI: 10.1016/S1567-8326(02)00039-5.

J.A. Bergstra and C.A. Middelburg. Located actions in process algebra with timing. Fundamenta Informaticae, 61(3/4):183--211, 2004.   Electronic version.

J.A. Bergstra and C.A. Middelburg. Process algebra for hybrid systems. Theoretical Computer Science, 335(2/3):215--280, 2005.   DOI: 10.1016/j.tcs.2004.04.019.

J.A. Bergstra and C.A. Middelburg. Continuity controlled hybrid automata. Journal of Logic and Algebraic Programming, 68(1/2):5--53, 2006.   DOI: 10.1016/j.jlap.2005.10.002.

J.A. Bergstra and C.A. Middelburg. Thread algebra with multi-level strategies. Fundamenta Informaticae, 71(2/3):153--182, 2006.   Electronic version.

C.A. Middelburg. Conditionals in algebraic process calculi. Electronic Notes in Theoretical Computer Science, 162:237--241, 2006.   DOI: 10.1016/j.entcs.2005.12.088.

J.A. Bergstra and C.A. Middelburg. Splitting bisimulations and retrospective conditions. Information and Computation, 204(7):1083--1138, 2006.   DOI: 10.1016/j.ic.2006.03.003.

J.A. Bergstra and C.A. Middelburg. Preferential choice and coordination conditions. Journal of Logic and Algebraic Programming, 70(2):172--200, 2007.   DOI: 10.1016/j.jlap.2006.08.004.

J.A. Bergstra and C.A. Middelburg. Thread algebra for strategic interleaving. Formal Aspects of Computing, 19(4):445--474, 2007.   DOI: 10.1007/s00165-007-0024-9.

J.A. Bergstra and C.A. Middelburg. A thread algebra with multi-level strategic interleaving. Theory of Computing Systems, 41(1):3--32, 2007.   DOI: 10.1007/s00224-006-1337-4.

J.A. Bergstra and C.A. Middelburg. Maurer computers with single-thread control. Fundamenta Informaticae, 80(4):333--362, 2007.   Electronic version.

J.A. Bergstra and C.A. Middelburg. Synchronous cooperation for explicit multi-threading. Acta Informatica, 44(7/8):525--569, 2007.   DOI: 10.1007/s00236-007-0057-9.

J.A. Bergstra and C.A. Middelburg. Instruction sequences with indirect jumps. Scientific Annals of Computer Science, 17:19--46, 2007.   Electronic version.

J.A. Bergstra and C.A. Middelburg. Programming an interpreter using molecular dynamics. Scientific Annals of Computer Science, 17:47--81, 2007.   Electronic version.

J.A. Bergstra and C.A. Middelburg. Simulating Turing machines on Maurer machines. Journal of Applied Logic, 6(1):1--23, 2008.   DOI: 10.1016/j.jal.2007.04.001.

J.A. Bergstra and C.A. Middelburg. Maurer computers for pipelined instruction processing. Mathematical Structures in Computer Science, 18(2):373--409, 2008.   DOI: 10.1017/S0960129507006548.

J.A. Bergstra and C.A. Middelburg. Distributed strategic interleaving with load balancing. Future Generation Computer Systems, 24(6):530--548, 2008.   DOI: 10.1016/j.future.2007.08.001.

J.A. Bergstra and C.A. Middelburg. Parallel processes with implicit computational capital. Electronic Notes in Theoretical Computer Science, 209:55--81, 2008.   DOI: 10.1016/j.entcs.2008.04.004.

J.A. Bergstra and C.A. Middelburg. Program algebra with a jump-shift instruction. Journal of Applied Logic, 6(4):553--563, 2008.   DOI: 10.1016/j.jal.2008.07.001.

J.A. Bergstra and C.A. Middelburg. Instruction sequences with dynamically instantiated instructions. Fundamenta Informaticae, 96(1--2):27--48, 2009.   DOI: 10.3233/FI-2009-165.

J.A. Bergstra and C.A. Middelburg. Machine structure oriented control code logic. Acta Informatica, 46(5):375--401, 2009.   DOI: 10.1007/s00236-009-0099-2.

J.A. Bergstra and C.A. Middelburg. A thread calculus with molecular dynamics. Information and Computation, 208(7):817--844, 2010.   DOI: 10.1016/j.ic.2010.01.004.

J.A. Bergstra and C.A. Middelburg. On the operating unit size of load/store architectures. Mathematical Structures in Computer Science, 20(3):395--417, 2010.   DOI: 10.1017/S0960129509990314.

J.A. Bergstra and C.A. Middelburg. An interface group for process components. Fundamenta Informaticae, 99(4):355--382, 2010.   DOI: 10.3233/FI-2010-254.

J.A. Bergstra and C.A. Middelburg. Data linkage dynamics with shedding. Fundamenta Informaticae, 103(1--4):31--52, 2010.   DOI: 10.3233/FI-2010-317.

J.A. Bergstra and C.A. Middelburg. Thread algebra for poly-threading. Formal Aspects of Computing, 23(4):567--583, 2011.   DOI: 10.1007/s00165-011-0178-3.

J.A. Bergstra and C.A. Middelburg. Inversive meadows and divisive meadows. Journal of Applied Logic, 9(3):203--220, 2011.   DOI: 10.1016/j.jal.2011.03.001.

J.A. Bergstra and C.A. Middelburg. Thread extraction for polyadic instruction sequences. Scientific Annals of Computer Science, 21(2):283--310, 2011.   Electronic version.

J.A. Bergstra and C.A. Middelburg. Preliminaries to an investigation of reduced product set finance. Journal of King Abdulaziz University: Islamic Economics, 24(1):175--210, 2011.   DOI: 10.4197/Islec.24-1.7.

J.A. Bergstra and C.A. Middelburg. On the expressiveness of single-pass instruction sequences. Theory of Computing Systems, 50(2):313--328, 2012.   DOI: 10.1007/s00224-010-9301-8.

J.A. Bergstra and C.A. Middelburg. Instruction sequence processing operators. Acta Informatica, 49(3):139--172, 2012.   DOI: 10.1007/s00236-012-0154-2.

J.A. Bergstra and C.A. Middelburg. On the behaviours produced by instruction sequences under execution. Fundamenta Informaticae, 120(2):111-144, 2012.   DOI: 10.3233/FI-2012-753.

J.A. Bergstra and C.A. Middelburg. Indirect jumps improve instruction sequence performance. Scientific Annals of Computer Science, 22(2):253--265, 2012.   DOI: 10.7561/SACS.2012.2.253.

J.A. Bergstra and C.A. Middelburg. A process calculus with finitary comprehended terms. Theory of Computing Systems, 53(4):645--668, 2013.   DOI: 10.1007/s00224-013-9468-x.

J.A. Bergstra and C.A. Middelburg. Data linkage algebra, data linkage dynamics, and priority rewriting. Fundamenta Informaticae, 128(4):367--412, 2013.   DOI: 10.3233/FI-2013-950.

J.A. Bergstra and C.A. Middelburg. Timed tuplix calculus and the Wesseling and van den Berg equation. Scientific Annals of Computer Science 23(2):169--190, 2013.   DOI: 10.7561/SACS.2013.2.169.

J.A. Bergstra and C.A. Middelburg. Instruction sequence based non-uniform complexity classes. Scientific Annals of Computer Science 24(1):47--89, 2014.   DOI: 10.7561/SACS.2014.1.47.

J.A. Bergstra and C.A. Middelburg. Division by zero in non-involutive meadows. Journal of Applied Logic, 13(1):1--12, 2015.   DOI: 10.1016/j.jal.2014.10.001.

J.A. Bergstra and C.A. Middelburg. On algorithmic equivalence of instruction sequences for computing bit string functions. Fundamenta Informaticae, 138(4):411--434, 2015.   DOI: 10.3233/FI-2015-1219.

J.A. Bergstra and C.A. Middelburg. Probabilistic thread algebra. Scientific Annals of Computer Science 25(2):211--243, 2015.   DOI: 10.7561/SACS.2015.2.211.

J.A. Bergstra and C.A. Middelburg. Transformation of fractions into simple fractions in divisive meadows. Journal of Applied Logic, 16:92--110, 2016.   DOI: 10.1016/j.jal.2016.03.001.

J.A. Bergstra and C.A. Middelburg. Instruction sequence size complexity of parity. Fundamenta Informaticae, 149(3):297--309, 2016.   DOI: 10.3233/FI-2016-1450.

J.A. Bergstra and C.A. Middelburg. On instruction sets for Boolean registers in program algebra. Scientific Annals of Computer Science 26(1):1--26, 2016.   DOI: 10.7561/SACS.2016.1.1.

J.A. Bergstra and C.A. Middelburg. A Hoare-like logic of asserted single-pass instruction sequences. Scientific Annals of Computer Science 26(2):125--156, 2016.   DOI: 10.7561/SACS.2016.2.125.

J.A. Bergstra and C.A. Middelburg. Contradiction-tolerant process algebra with propositional signals. Fundamenta Informaticae, 153(1--2):29--55, 2017.   DOI: 10.3233/FI-2017-1530.

J.A. Bergstra and C.A. Middelburg. Axioms for behavioural congruence of single-pass instruction sequences. Scientific Annals of Computer Science 27(2):111--135, 2017.   DOI: 10.7561/SACS.2017.2.111.

J.A. Bergstra and C.A. Middelburg. Instruction sequences expressing multiplication algorithms. Scientific Annals of Computer Science 28(1):39--66, 2018.   DOI: 10.7561/SACS.2018.1.39.

J.A. Bergstra and C.A. Middelburg. A short introduction to program algebra with instructions for Boolean registers. Computer Science Journal of Moldova, 26(3):199--232, 2018.   Electronic version.

J.A. Bergstra and C.A. Middelburg. Program algebra for Turing-machine programs. Scientific Annals of Computer Science, 29(2):113--139, 2019.   DOI: 10.7561/SACS.2019.2.113.

J.A. Bergstra and C.A. Middelburg. Process algebra with strategic interleaving. Theory of Computing Systems, 63(3):488--505, 2019.   DOI: 10.1007/s00224-018-9873-2.

J.A. Bergstra and C.A. Middelburg. On the complexity of the correctness problem for non-zeroness test instruction sequences. Theoretical Computer Science, 802:1--18, 2020.   DOI: 10.1016/j.tcs.2019.03.040.

C.A. Middelburg. Probabilistic process algebra and strategic interleaving. Scientific Annals of Computer Science, 30(2):205--243, 2020.   DOI: 10.7561/SACS.2020.2.205.

C.A. Middelburg. On the strongest three-valued paraconsistent logic contained in classical logic and its dual. Journal of Logic and Computation, 31(2):597--611, 2021.   DOI: 10.1093/logcom/exaa084.

J.A. Bergstra and C.A. Middelburg. Using Hoare logic in a process algebra setting. Fundamenta Informaticae, 179(4):321--344, 2021.   DOI: 10.3233/FI-2021-2026.

Conference papers

C.A. Middelburg. The effect of the PDP11 architecture on code generation for CHILL. In Proceedings ACM Symposium on Architectural Support for Programming Languages and Operating Systems, pages 149--157, 1982.   DOI: 10.1145/960120.801838.

C.A. Middelburg. The VIP VDM specification language. In R. Bloomfield, L. Marshall and R. Jones, editors, VDM '88, pages 187--201. Springer Verlag, LNCS 328, 1988.   DOI: 10.1007/3-540-50214-9_17.

C.A. Middelburg. Experiences with combining formalisms in VVSL. In J.A. Bergstra and L.M.G. Feijs, editors, Algebraic Methods II: Theory, Tools and Applications, pages 83--103. Springer Verlag, LNCS 490, 1991.   DOI: 10.1007/3-540-53912-3_19.

C.A. Middelburg and G.R. Renardel de Lavalette. LPF and MPLomega -- a logical comparison of VDM SL and COLD-K. In S. Prehn and W.J. Toetenel, editors, VDM '91, pages 279--308. Springer Verlag, LNCS 551, 1991.   DOI: 10.1007/3-540-54834-3_18.

C.A. Middelburg. VVSL specification of a transaction-oriented access handler. In D.J. Harper and M.C. Norrie, editors, Specifications of Database Systems, pages 188--212. Springer Verlag, Workshops in Computing Series, 1992.   DOI: 10.1007/978-1-4471-3864-8_10.

L.G. Bouma, W.G. Levelt, A.A.J. Melisse, C.A. Middelburg and L. Verhaard. Formalisation of properties for feature interaction detection: experience in a real-life situation. In H.-J. Kugler, A. Mullery and N. Niebert, editors, IS&N '94, pages 393--405. Springer-Verlag, LNCS 851, 1994.   DOI: 10.1007/BFb0013431.

J.A. Bergstra and C.A. Middelburg. Process algebra semantics of phiSDL. In A. Ponse, C. Verhoef and S.F.M. van Vlijmen, editors, ACP '95, pages 309--346. Report 95-14, Eindhoven University of Technology, Department of Computing Science, 1995.

Yuan Zhaorui, Yang Fangchun and C.A. Middelburg. Detection of non-determinacy feature interaction. In Communications 1999, volume 2, pages 1231--1235. Publishing House BUPT, Beijing, China, 1999.   DOI: 10.1109/APCC.1999.820485.

Yuan Zhaorui, Yang Fangchun and C.A. Middelburg. Detection of livelock feature interaction. In Future Telecommunications Forum '99. Publishing House BUPT, Beijing, China, 1999.

J.A. Bergstra and C.A. Middelburg. A thread algebra with multi-level strategic interleaving. In S.B. Cooper, B. Loewe and L. Torenvliet, editors, CiE 2005, pages 35--48. Springer-Verlag, LNCS 3526, 2005.   DOI: 10.1007/11494645_5.

J.A. Bergstra and C.A. Middelburg. Strong splitting bisimulation equivalence. In J.L. Fiadeiro, N. Harman, M. Roggenbach and J. Rutten, editors, CALCO 2005, pages 85--99. Springer-Verlag, LNCS 3629, 2005.   DOI: 10.1007/11548133_6.

J.A. Bergstra and C.A. Middelburg. Model theory for process algebra. In A. Middeldorp, V. van Oostrom, F. van Raamsdonk and R.C. de Vrijer, editors, Processes, Terms and Cycles: Steps on the Road to Infinity, pages 445--495. Springer-Verlag, LNCS 3838, 2005.   DOI: 10.1007/11601548_21.

J.A. Bergstra and C.A. Middelburg. Transmission protocols for instruction streams. In M. Leucker and C. Morgan, editors, ICTAC 2009, pages 127--139. Springer-Verlag, LNCS 5684, 2009.   DOI: 10.1007/978-3-642-03466-4_8.

Preprints

C.A. Middelburg. A simple language for expressing properties of telecommunication services and features. Publication 94-PU-356, PTT Research, 1994.

J.A. Bergstra, W.J.Fokkink and C.A. Middelburg. A logic for signal inserted timed frames. Logic Group Preprint Series 155, Utrecht University, Department of Philosophy, January 1996.

J.A. Bergstra, C.A. Middelburg and R. Soricut. Discrete time network algebra for a semantic foundation of SDL. UNU/IIST Report 98, The United Nations University, International Institute for Software Technology, October 1997.

J.A. Bergstra, C.A. Middelburg and B. Warinschi. Timed frame models for discrete time process algebras. UNU/IIST Report 100, The United Nations University, International Institute for Software Technology, October 1997.

J.C.M. Baeten, C.A. Middelburg and M.A. Reniers. A new equivalence for processes with timing. Computing Science Report 02-10, Eindhoven University of Technology, Department of Mathematics and Computing Science, October 2002.

J.A. Bergstra and C.A. Middelburg. Process algebra with conditionals in the presence of epsilon. Computing Science Report 05-15, Eindhoven University of Technology, Department of Mathematics and Computing Science, May 2005. Revised version available from http://arxiv.org/: arXiv:1204.3249v1 [cs.LO].

J.A. Bergstra and C.A. Middelburg. Instruction sequences and non-uniform complexity theory. Electronic Report PRG0812, University of Amsterdam, Programming Research Group, September 2008. Available from http://www.science.uva.nl/research/prog/publications.html. Revised version available from http://arxiv.org/: arXiv:0809.0352v3 [cs.CC].

J.A. Bergstra and C.A. Middelburg. Instruction sequences for the production of processes. Electronic Report PRG0814, University of Amsterdam, Programming Research Group, November 2008. Available from http://www.science.uva.nl/research/prog/publications.html. Revised version available from http://arxiv.org/: arXiv:0811.0436v2 [cs.PL].

J.A. Bergstra and C.A. Middelburg. Instruction sequence notations with probabilistic instructions. Electronic Report PRG0906, University of Amsterdam, Programming Research Group, June 2009. Available from http://www.science.uva.nl/research/prog/publications.html. Revised version available from http://arxiv.org/: arXiv:0906.3083v2 [cs.PL].

J.A. Bergstra and C.A. Middelburg. On the definition of a theoretical concept of an operating system. Available from http://arxiv.org/: arXiv:1006.0813v1 [cs.OS].

C.A. Middelburg. A survey of paraconsistent logics. Available from http://arxiv.org/: arXiv:1103.4324v3 [cs.LO].

J.A. Bergstra and C.A. Middelburg. An application specific informal logic for interest prohibition theory. Available from http://arxiv.org/: arXiv:1104.0308v1 [q-fin.GN].

J.A. Bergstra and C.A. Middelburg. Turing impossibility properties for stack machine programming. Available from http://arxiv.org/: arXiv:1201.6028v1 [cs.LO].

J.A. Bergstra, C.A. Middelburg, and Gh. Stefanescu. Network algebra for synchronous dataflow. Available from http://arxiv.org/: arXiv:1303.0382v1 [cs.LO].

J.A. Bergstra and C.A. Middelburg. Instruction sequence expressions for the secure hash algorithm SHA-256. Available from http://arxiv.org/: arXiv:1308.0219v7 [cs.PL].

C.A. Middelburg. Process algebra, process scheduling, and mutual exclusion. Available from http://arxiv.org/: arXiv:2003.00473v3 [cs.LO].

R.J. van Glabbeek and C.A. Middelburg. On infinite guarded recursive specifications in process algebra. Available from http://arxiv.org/: arXiv:2005.00746v1 [cs.LO].

C.A. Middelburg. Program algebra for random access machine programs. Available from http://arxiv.org/: arXiv:2007.09946v2 [cs.PL].

C.A. Middelburg. A classical-logic view of a paraconsistent logic. Available from http://arxiv.org/: arXiv:2008.07292v2 [cs.LO].

C.A. Middelburg. Imperative process algebra with abstraction. Available from http://arxiv.org/: arXiv:2103.07863v3 [cs.LO].

C.A. Middelburg. Dormancy-aware timed branching bisimilarity for timed analysis of communication protocols. Available from http://arxiv.org/: arXiv:2107.08921v3 [cs.LO].

Other Publications

C.A. Middelburg. A formal definition based design of the translation phase of a CHILL compiler. In Proceedings CHILL Implementors/Users Meeting, Technical University of Denmark, Lyngby, 1980.

C.A. Middelburg. Combining VDM and temporal logic. Proceedings Workshop on Specification of Concurrent Systems, Philips Research Laboratories, Eindhoven, 1989.

C.A. Middelburg. A framework for defining modular structuring facilities. Proceedings Modules Meeting, National Physical Laboratory, Teddington, 1992.

C.A. Middelburg. Design calculi in software development: Theory and practice. In Proceedings EU-China High Tech Conference, pages 307--311. SSTCC and EU DG XII, 1996.

C.A. Middelburg. Beyond SDL. UNU/IIST Lecture Notes: DesCaRTeS Course, The United Nations University, International Institute for Software Technology, 1997.

C.A. Middelburg. Searching publications on operating systems. Available from http://arxiv.org/: arXiv:1003.5525v1 [cs.OS].

C.A. Middelburg. Searching publications on software testing. Available from http://arxiv.org/: arXiv:1008.2647v1 [cs.SE].

J.A. Bergstra and C.A. Middelburg. Interest prohibition and financial product innovation. In A. Escurat, editor, Finance Islamique: Regard(s) sur une Finance Alternative, pages 274--284. Mazars Hadj Ali, Algiers, 2011.

C.A. Middelburg. A short introduction to process theory. Available from http://arxiv.org/: arXiv:1610.01412v1 [cs.LO].

Publications in Dutch

C.A. Middelburg. Het relationele model gezien in het licht van de Codasyl voorstellen. Informatie, 17(2):67--76, 1975.

C.A. Middelburg. Een beschouwing over informatiesystemen en databasemanagement. Het PTT-Bedrijf, 20(4):221--224, 1977.

C.A. Middelburg and J. Mendrik. Een ingenieurskijk op Teletekst en Viewdata: Technische achtergronden. De Ingenieur, 90(48):927--932, 1978.

C.A. Middelburg. Prolog: Programmeren in logica? Informatie, 26(11):866--870, 1984.

C.A. Middelburg. Programmeren in logica. In J.A.A.M. Poirters and G.J. Schoenmakers, editors, Colloquium Programmeertalen, pages 39--60. Academic Service, 1986.

C.A. Middelburg. Is programmatuurontwikkeling met formele methoden zinvol? Informatie, 34(3):148--158, 1992.

C.A. Middelburg. Programmatuur zonder Logica. Inaugural lecture, Utrecht University, Department of Philosophy, 1993.