Academic scratchings

• Instrumental Artifact Functions and Normativity. A chapter in the Norms in Technology issue of Philosophy of Engineering and Technology.
• , chapter in Philosophy of Technology and Engineering Sciences, Anthonie Meijers ed.
• An Artifact is to Use. An introduction to my theory of instrumental functions. Published in Synthese 168.
• Don't Ever Do That! with Lamber Royakkers. This paper examines long-term prohibitions and obligations in J.-J. Meyer's Dynamic Deontic Logic (PDeL). Published in Studia Logica volume 89 no. 1.
• A Semantics for Means-end Relations, published in Synthese 158. With Peter Kroes and Sjoerd Zwart.
• Means-end Semantics and a Measure of Efficacy, presented at Progic 2005 and accepted for publication in the associated JoLLI issue. Our first submitted work on fuzzy dynamic logic and means-end relations. With Albert Esterline and Bahram Kimiaghalam.
• Admissible Digit Sets, to be published in the special issue of Theoretical Computer Science on Real Numbers and Computers, with Milad Niqui. There is also a longer tech report here. See also the errata sheet.
• Simulations in Coalgebra, to be published in TCS, with Bart Jacobs. This is an extension of a paper of the same name published in ENTCS 82(1), 2003 (Special issue on the conference of CMCS 2003).
• Concise Graphs and Functional Bisimulations, presented at CMCIM 03 by coauthor Ling Cheung.
• The Coinductive Approach to Verifying Cryptographic Protocols, to appear in the WADT 2002 proceedings, with Martijn Warnier.
• Factorization Systems and Fibrations, in ENTCS 69 (special issue for CTCS 2002), with Bart Jacobs.
• Some Co-Birkhoff-Type Theorems, in ENTCS 65(1) for CMCS 2002.
• Distributivity of Classes of Coalgebras, in TCSB, with Peter Gumm and Tobias Schroeder.
• A Study of Categories of Algebras and Coalgebras, dissertation. Also available in A4 gzipped ps, pdf or gzipped dvi.
• Modal Operators and the Formal Dual of Birkhoff's Completeness Theorem in MSCS 13, with Steve Awodey.
• The Coalgebraic Dual of Birkhoff's Variety Theorem, Technical Report CMU-PHIL-109 with Steve Awodey.
• Our Friend, The Beaver, submitted in partial fulfillment of the requirements for fourth grade English class, under the supervision of Ms. Laskey.

Conference papers

• A Semantics for Functional Efficacy, a draft of a paper to be presented at the Society for Philosophy of Technology conference in Delft this July. This paper brings together the fuzzy dynamic logic from our Progic 2005 submission with the artifactual function semantics from the Norms, Reasoning and Knowledge in Technology Workshop paper. In doing so, we give a definition of one important kind of malfunction. With Sjoerd Zwart.
• Means-end relations and Artifactual Functions: a Sketch, a draft of a paper to be presented at the Norms, Reasoning and Knowledge in Technology Workshop in Boxmeer this June. This is my first attempt to present the relationship between means-end relations and functional ascriptions.
• A Semantics for Means-End Relations, accepted for SEP 2005. This is a fairly broad overview of our means-end semantics, with discussion of sufficient and necessary means, sufficient and necessary preconditions, the need for non-monotonic conditionals, and so on. The final section sketches why we feel monotone neighborhood semantics is more appropriate than the Kripke semantics we use here, and also mentions efficacy via fuzzy dynamic logic. With Peter Kroes and Sjoerd Zwart.

Drafts and unpublished work

• From Functions to Means. This is a non-technical discussion of how artifactual functions produce means-end relations. It is inspired by the formal semantics in Means-end relations and Artifactual Functions. (The lazy reader can check the older, shorter version.)
• "Means" Means What?, an early version of our work on means-end relations. This article is largely superseded by A Semantics for Means-end Relations. See also the short version of "'Means' Means What?" for a different example of a means-end model (but aside from the example, the long version is a superset of the short).
• Fuzzy Dynamic Logic, a working draft of some work on fuzzy set semantics for dynamic logic. This is a longer, more technical presentation of the material in A Measure of Efficacy, with much material not discussed there. With Albert Esterline and Bahram Kimiaghalam.
• Dynamic Logic with Likelihoods, an unpublished abstract about likelihoods and means-end ascriptions. This abstract suggests two different semantics for means-end logic, both of which incorporate likelihoods. The first semantics, the simple semantics, is essentially a fuzzy set semantics, but I didn't realize it at the time. The second semantics is more complicated, in fact, is not truth-functional. I still find the comparison between the two interesting, but I doubt that I will publish anything along these lines.