Vol. 20 Num. 1 (2000) Ole Skovsmose Aporism and critical mathematics education2 Karin Brodie Teacher intervention in small-group work9 Roza Leikin , Greisy Winicki-Landman On equivalent and non-equivalent definitions: part 117 Gotz Krummheuer Mathematics learning in narrative classroom cultures: studies of argumentation in primary mathematics education22 Mary Barnes 'Magical' moments in mathematics: insights into the process of coming to know33 Constantinos Tzanakis , Yannis Thomaidis Integrating the close historical development of mathematics and physics in mathematics education: some methodological and epistemological remarks44