Kellerman, Ruaan2015-09-162015-09-162015-08Kellerman, R 2015, 'First-order aspects of tree paths', Logic Journal of the IGPL, vol. 23, no. 4, pp. 688-704.1367-0751 (print)1368-9894 (online)10.1093/jigpal/jzv026http://hdl.handle.net/2263/49950Tree paths are investigated using first-order logic. The following results are obtained: (i) every definable path can be defined by a firstorder formula using at most one parameter chosen from the path itself; (ii) a canonical representation of the formulas that define definable paths is obtained; and (iii) every tree that has only finitely many paths that are not definable is n-equivalent to a tree of which all paths are definable. Moreover, a certain property that might be expected to hold, involving the transfer of n-equivalence between trees, is shown not to be true.en© The Author 2015. Published by Oxford University Press. All rights reserved. This is a pre-copy-editing, author-produced PDF of First-order aspects of tree paths in Logic Journal of the IGPL, vol. 23, no. 4, pp. 688-704, 2015. doi : 10.1093/jigpal/jzv026. The definitive publisher-authenticated version is available online at : http//jigpal.oxfordjournals.org.Tree pathsFirst-order logicPostprint Article