Eve A. Torrence

“Shutting up like a telescope”: Lewis Carroll's “Curious” Condensation Method for Evaluating Determinants

Adrian Rice (arice4@rmc.edu) received a B.Sc. in mathematics from University College London in 1992 and a Ph.D. in the history of mathematics from Middlesex University in 1997 for a dissertation on Augustus De Morgan. He is currently an associate professor of mathematics at Randolph-Macon College in Ashland, Virginia, where his research focuses on 19thand early 20th-century British mathematics. His recent publications include Mathematics Unbound: The Evolution of an International Mathematical Research Community, 1800–1945, edited with Karen Hunger Parshall, and The London Mathematical Society Book of Presidents, 1865–1965, written with Susan Oakes and Alan Pears.

Computing Determinants by Double-Crossing

Summary Dodgsons method of computing determinants is attractive, but fails if an interior entry of an intermediate matrix is zero. This paper reviews Dodgsons method and introduces a generalization, the double-crossing method, that provides a workaround for many interesting cases.Dodgson’s method of computing determinants was recently revisited in a paper that appeared in the College Math Journal. The method is attractive, but fails if an interior entry of an intermediate matrix has the value zero. This paper reviews the structure of Dodgson’s method and introduces a generalization, called a “double-crossing” method, that provides a workaround to the failure for many interesting cases.

The Student's Introduction to Mathematica ®: Working with Mathematica

Practical information to and tips for using Mathematica and the Wolfram Language. Document creation, slideshow presentations, keyboard shortcuts, documentation, and troubleshooting are discussed.