J. Pais. The Topology of Nonmonotonicity. The European Summer Meeting of the Association for Symbolic Logic (Logic Colloquium '93), University of Keele, Great Britain, 1993. 

J. Pais. Exterior Topology as a Framework for Knowledge Base Revision. Eighth Summer Conference on General Topology and Applications, Queens College CUNY, Flushing, NY, 1992. 

J. Pais. Exterior Topology. Missouri Meeting of the Mathematical Association of America, Northwest Missouri State University, Maryville, MO, 1992. 

J. Pais. Partially Monotonic Revision Operators for Revising Deductive Databases. Second International Conference on Industrial and Applied Mathematics, Sheraton Washington Hotel, Washington, DC, 1991. 

J. Pais. Nonmonotonic Clause Management Systems for Revising Plan Assumptions. DARPA Conference on Associate Technology, George Mason University, Fairfax, VA, 1991.

J. Pais. Nonmonotonic Logic. Missouri Meeting of the Mathematical Association of America, University of Missouri-Rolla, Rolla, MO, 1991. 

J. Pais. Partial Monotonicity and a New Version of the Ramsey Test. Third International Conference on Theoretical Aspects of Reasoning about Knowledge, Asilomar Conference Center, Pacific Grove, CA, 1990.