Stephen G. Simpson. Nonprovability of certain combinatorial properties of finite trees. Harvey Friedman's research on the foundations of mathematics, edited by L. A. Harrington, M. D. Morley, A. Ṧčedrov, and S. G. Simpson, Studies in logic and the foundations of mathematics, vol. 117, North-Holland, Amsterdam, New York, and Oxford, 1985, pp. 87–117. (English translation of Nichtbeweisbarkeit von gewissen kombinatorischen Eigenschaften endlicher Bäume, Archiv für mathematische Logik und Grundlagenforschung, vol. 25 (1985), pp. 45–65.)
1990 ◽
Vol 55
(2)
◽
pp. 868-869