Although proof comprehension is fundamental in advanced undergraduate mathematics courses, there has been limited research on what it means to understand a mathematical proof at this level and how such understanding can be assessed. In this paper, we address these issues by presenting a multidimensional model for assessing proof comprehension in…

Instructions are given for building a flexible model used for illustrating an elliptic paraboloid, a parabolic cylinder, and a hyperbolic paraboloid. (DT)

A short account is given of the Coxeter Symposium on geometry. Included are brief descriptions of selected sessions and a description of a touchable geometry display. (MK)

Presents an allegory to illustrate the problem of testing an axiomatic system. A fictitious discussion begins by examining an axiomatic system underlying the intercom system of an association. The discussion continues to examine an unusual model of Euclidean geometry and a model of the noneuclidean geometry discovered by Lobachevsky. (MDH)

Proposes a real-time collaborative framework for geometric modeling. Assessment results show that the collaborative environment was useful in design education. (MM)

Describes how many of the geometrical and physical properties of the binary elastic collision of two particles can be represented by an isoceles trapezoid in the velocity space. (BB)

Presents a reexamination of an intuitively geometric view of the nonrelativistic Pauli spinor in a simplified discussion of the connection between the rotation group and special transformations in the plane of projection. This view of the spinor is related to those based on the existence of an istropic or null vector. (SK)

Shows that the experiment of the ancient Greek mathematician and geographer, Eratosthenes, can be replicated and used to teach geographic concepts. Eratosthenes calculated the most accurate ancient measurement of earth based on fundamental mathematics concepts and earth-sun relations. Includes instructions, illustrations, graphs, and historical…

Discussed are various models proposed for the Moebius strip. Included are a discussion of a smooth flat model and two smooth flat algebraic models, some results concerning the shortest Moebius strip, the Moebius strip of least elastic energy, and some observations on real-world Moebius strips. (KR)

An introductory preservice teacher activity from a typical college geometry course is presented. This activity leads the preservice teachers to specific goals, including increased geometric awareness within the everyday environment, appreciation for mathematical modeling techniques, and awareness of methods for teaching geometric concepts to…

Cabri3D is a potentially very useful software for learning and teaching 3D geometry. The dynamic nature of the digital diagrams produced with it provides a useful aid for helping students to better develop concept images of geometric concepts. However, since any Cabri3D diagram represents three-dimensional objects on the two dimensional screen of…

The Proceedings of PME-XVIII have been published in four separate volumes because of the large number of individual conference papers reported. Volume I contains brief reports for 11 Working Groups and 8 Discussion Groups, 55 "Short Oral Communications," 28 Posters, 5 Plenary Panel reports, and 4 Plenary Session reports. Volume II…

This document contains the second volume of the proceedings of the 30th Annual Conference of the International Group for the Psychology of Mathematics Education. Conference presentations are centered around the theme "Mathematics at the Centre." This volume features 60 research reports by presenters with last names beginning between Abr…