Thesis (Ph. D.)--University of Chicago, 1903. / Life. "Reprinted from the Transactions of the American mathematical society, vol. 5, no. 3."

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Six experiments tested the assumption that, in visual perception, observers have reliable and direct access to the equivalence of shapes in projective geometry (I call this "the invariance hypothesis in the theory of shape constancy"). This assumption has been made in the study of vision since Helmholtz's time. Two experiments tested recognition of the projective equivalence of planar shapes. In another four experiments, subjects estimated the apparent shape of a solid object from different perspectives. Departure from projective equivalence was assessed in each study by measuring the cross ratio for the plane. This measure of projective invariance is new to perceptual research. Projective equivalence was not found to be perceived uniformly in any of the studies. A significant effect of change in perspective was found in each study. These results were construed as supporting the classical theory of depth cues against the invariance hypothesis.

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Bibliography: leaves 211-217 / vii, 217 leaves ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Pure Mathematics, 1988

This thesis concerns sets of points in the finite projective space PG(n,q) that are combinatorially identical to quadrics. A quadric is the set of points of PG(n,q) whose coordinates satisfy a quadradic equation, and the term quadral is used in this thesis to mean a set of points with all the combinatorial properties of a quadric. Most of the thesis concerns the characterisation of certain sets of subspaces associated with quadrals. Characterisations are proved for the external lines of an oval cone in PG(3,q), of a non-singular quadric in PG(4,q), q even, and of a large class of cones in PG(n,q), q even. Characterisations are also proved for the planes meeting the non-singular quadric of PG(4,q) in a non-singular conic, and for the tangents and generator lines of this quadric for q odd. The second part of the thesis is concerned with the intersection of ovoids of PG(3,q). A new bound is proved on the number of points two ovoids can share, and configurations of secants and external lines that two ovoids can share are determined. The structure of ovoidal fibrations is discussed, and this is used to prove new results on the intersection of two ovoids sharing all of their tangents. / Thesis (Ph.D.) -- University of Adelaide, School of Mathematical Sciences, 2008

Univ., Diss.--Leiden, 1990. / Literaturverz. S. 141 - 146.

Thesis (Ph. D.)--Princeton University, 1910.

Thesis (Ph.D.) -- University of Adelaide, School of Mathematical Sciences, Discipline of Pure Mathematics, 2008. / "Submitted May 2008" Bibliography: pages 191-195. Also available in print form.

Thesis (Ph. D.)--Catholic University of America, 1942. / Reproduced from type-written copy.