1. School of Mathematics, University of Leeds, Leeds, LS2 9JT, England. R.H.Elwes@leeds.ac.uk
2. Department of Mathematics, Columbia House, London School of Economics, Houghton Street, London, WC2A 2AE, England. a.lewis7@lse.ac.uk
3. Institute for Logic, Language and Computation, Universiteit van Amsterdam, Postbus 94242, 1090 GE Amsterdam, The Netherlands
4. Fachbereich Mathematik, Universität Hamburg, Bundesstraße 55, 20146 Hamburg, Germany
5. Churchill College & Faculty of Mathematics, University of Cambridge, Storey’s Way, Cambridge, CB3 0DS, England. bloewe@science.uva.nl
6. School of Mathematics, University of Leeds, Leeds, LS2 9JT, England. H.D.MacPherson@leeds.ac.uk
7. Matematisk Institutt, Universitetet i Oslo, Postboks 1053, Blindern, 0316 Oslo, Norway. dnormann@math.uio.no
8. Dipartimento di Ingegneria dell’Informazione e Scienze Matematiche, Università di Siena, Via Roma 56, 53100 Siena, Italy. sorbi@unisi.it
9. Faculty of Mathematics and Computer Science, Sofia University, 5 James Bourchier Blvd, 1164 Sofia, Bulgaria. asoskova@fmi.uni-sofia.bg
10. Department of Mathematics, University of Wisconsin–Madison, 480 Lincoln Drive, Madison, WI 53706, United States of America. msoskova@masth.wisc.edu
11. Institute for Logic, Language and Computation, Universiteit van Amsterdam, Postbus 94242, 1090 GE Amsterdam, The Netherlands. P.vanEmdeBoas@uva.nl
12. School of Mathematics, University of Leeds, Leeds, LS2 9JT, England. S.S.Wainer@leeds.ac.uk