[F1] The order extension principle Proceedings of Symposia in Pure Mathematics, Volume XIII, Part II, edited by T. Jech, (American Mathematical Society 1974), 179-183; MR 50 # 12717

(My first serious piece of research, written in 1967: it uses forcing to construct a model of ZF in which every set has a linear ordering, but some partial ordering cannot be extended to a linear ordering.)

[F2] (with R.D.Kopperman) Some problems in group theory, The Syntax and Semantics of Infinitary Languages, edited by J. Barwise, Springer Lecture Notes in Mathematics 72 (1968), 131-138

(Explains the resemblance to the L\"owenheim--Skolem theorem of theorems of Philip Hall about certain classes of infinite groups by showing that those classes are axiomatisable in weak second-order logic.)

[F3] Solution of problems of Choquet and Puritz Logic Colloquium '70 edited by W. Hodges, Springer Lecture Notes in Mathematics , 255, 204-210; MR 51 # 166

(Assuming the continuum hypothesis, a non-principal ultrafilter with no $p$-point below it in the Rudin-Keisler ordering, is constructed as a union of strictly smaller analytic filters. Here and below ``analytic" is the familiar concept from classical descriptive set theory developed by Lusin, Souslin, Sierpi\'nski and others.)

[F4] (with A.J.Ostaszewski and M. Talagrand) On the existence of an analytic set meeting each compact set in a Borel set, Mathematical Proceedings of the Cambridge Philosophical Society, 84 (1978) 5-10; MR 58 # 233

(Question: Is there an analytic but not Borel subset of Baire space that intersects each compact subset in a Borel set ? Answer: Yes if V=L; no if MA and not-CH.)

[F5] Unsound ordinals, Mathematical Proceedings of the Cambridge Philosophical Society, 96 (1984) 391-411; MR 86f:03075. doi:10.1017/S0305004100062319

(Shows that the answer to a question of Woodin depends crucially on whether or not every well-orderable set of reals is countable.)

[F6] On a conjecture of Erdős and Čudakov

(establishes a simple case of an unsolved problem. In: Combinatorics, Geometry and Probability: Proceedings of the conference dedicated to Paul Erdős on the occasion of his 80th birthday, edited by Bollobas Bela et al, Cambridge University Press (1993), 487--488.) .ps.dvi

[F7] A Term of Length 4,523,659,424,929 Synthese 133 (2002) 75--86 .ps .dvi

(A calculation of the number of symbols required to give Bourbaki's definition of the number 1; to which must be added 1,179,618,517,981 disambiguatory links. The implications for Bourbaki's philosophical claims and the mental health of their readers are discussed.)

[F8] A note on the schemes of replacement and collection Archive for Mathematical Logic, 46 (2007) 43-50. .ps .dvi

(derives all the axioms of ZF from a scheme that is apparently weaker than either the collection or the replacement scheme.)

[F9] A brief note on doubles tournaments, Eureka 60 (2010) page 41.

(Gives short solutions, using finite fields, of certain cases of the doubles problem and the spouse-avoiding doubles problem.)