John Lindsay Orr


  1. A quick introduction to the PageRank algorithm and some results on it.
  2. A lecture for high school students covering the need for internet security, the concept of public key cryptography, a sketch of the RSA algorithm, and implementation issues including man-in-the-middle attacks and certifiacte authorities.
  3. A description of the negative solution to Hilbert's Tenth Problem, concerning the undecidability of Diophantine equations. This 50 minute talk was given to UNL's Department of Mathematics Graduate Student Seminar in September, 2005.
  4. This talk presents an open problem on the algebra of upper triangular operators: What are the maximal (two-sided) ideals of this algebra? The talk discusses connections with other open problems and contrasts with the case of continuous nest algebras, for which the question can be answered.
  5. Describing research work on a simplified description and full classification of the stable (i.e. automorphism invariant) ideals of a continuous nest algebra. This talk was given at the GPOTS conference in June, 2005. The talk describes work for my paper "The Stable Ideals of a Continuous Nest Algebra, II".
  6. Describing joint work with Stephen Scott and Travis Fisher on Monte-Carlo algorithms to determine equivalence of mathematical expressions. The talk was given at the Spring 2005 sectional meeting of the MAA. See the paper "Randomized Interval Analysis Checks for the Equivalence of Mathematical Expressions".
  7. An overview of the advantages and disadvantages of online assessment management systems, with detail on EDU, MapleTA, and the UNL experience.
  8. A presentation I gave at the start of the week-long faculty EDU workshop in May 2005 supported by our ASA grant. This talk gives an overview of EDU's capabilities and its history and use at UNL. I also gave a second talk at the end of the workshop.