Exterior Boundary-value Problem with Application in General Relativity, AMS Special Session on Nonlinear PDEs and Applications, University of Illinois at Urbana-Champaign, March 27-29, 2009.

Constrained Hyperbolic Equations: Mathematical and Numerical Analysis, Penn State University, October 27, 2008.

Boundary Conditions for Hyperbolic Systems with Constraints, World Congress of Nonlinear Analysts, Orlando, Florida, July 2-9, 2008.

Boundary Conditions for Elliptic and Constrained Hyperbolic Equations: Mathematical and Numerical Analysis, Northern Illinois University, DeKalb, February 1^st, 2008.

Essential Boundary Conditions for Elliptic Equations in the Generalized Finite Element Method, SIAM Conference on Analysis of Partial Differential Equations, December 10 - 12, 2007, at the Hilton Phoenix East/Mesa, Mesa, Arizona.

Positive Radial Solutions to an Exterior Boundary-value Problem, Seventh Mississippi State – UAB Conference on Differential Equations & Computational Simulations, Birmingham, AL, November 1-3, 2007.

Approximate and Low Regularity Dirichlet Boundary Conditions in the Generalized Finite Element Method, Finite Element Methods in Engineering and Science (FEMTEC 2006), University of Texas at El Paso, December 11-15, 2006.

On the Initial-Boundary Value Problem for Constrained Hyperbolic Systems, AMS Special Session on Boundary Value Problems for Differential Equations with Applications, University of Cincinnati, October 21-22, 2006.

Geometric Boundary Conditions for a Constrained First Order Hyperbolic System of Differential Equations, AMS Special Session on Analysis and Geometry of Non-linear Evolution Equations, University of Notre Dame, April 8-9, 2006.

On the Existence and Uniqueness of the Conformal Factor in General Relativity, AMS Special Session on Partial Differential Equations with Applications, University of Oregon, Eugene, OR, November 11-13, 2005.

Boundary Conditions for a First Order Hyperbolic Formulation of Einstein’s Equations, The Sixth Mississippi State –UAB Conference on Differential Equations & Computational Simulations, May 13-14, 2005.

PCA Workshop III: Relativistic Astrophysics, Institute for Pure and Applied Mathematics (IPAM) – UCLA, May 2-6, 2005.

Constraint Preserving Boundary Conditions in Numerical Relativity, BIRS Workshop on Numerical Relativity, Pacific Institute for Mathematical Sciences, Banff, Canada, April 16-21, 2005.

On the Hamiltonian Constraint in General Relativity, 28^th Annual Texas Partial Differential Equations Conference, University of Texas - Pan American, March 19-20, 2005.

Constraint-preserving Boundary Conditions for Some Hyperbolic Systems of Differential Equations, AMS Session on Partial Differential Equations, Atlanta, GA, January 5-8, 2005.

Boundary Conditions for a Constrained Hyperbolic System, Finite Element Circus, Syracuse University, October 15-16, 2004.

Constraint Preserving Boundary Conditions for a Hyperbolic Formulation of Einstein’s Equations, AMS Sectional Meeting, Northwestern University, Evanston, IL, October 22-23, 2004.

Boundary Conditions for a Hyperbolic Formulation of Einstein's Equations, Applied Math. Seminar, University of Minnesota, April 1, 2004.

Boundary Conditions for Einstein's Equations, Math. Colloquium, North Dakota State University, March 23, 2004.

Boundary Conditions for Einstein's Equations, Math. Colloquium, Purdue University Calumet, February 26, 2004.

Boundary Conditions for Einstein's Equations, Math. Colloquium, California State University Hayward, February 19, 2004.

Maximal nonnegative constraint-preserving boundary conditions for the linearized Einstein equations, AMS Special Session on PDEs and Applications, Phoenix, AZ, January 7-10, 2004.

Well-posed constraint preserving boundary conditions for the linearized ADM decomposition, Finite Element Circus, Cornell University, November 7-8, 2003.

The linearized Einstein equations as initial value boundary problem, DDF Seminar, University of Minnesota, October 1, 2003.

Boundary conditions for a new first order symmetric hyperbolic formulation of Einstein's equations, University of Notre Dame, Conference on PDE and Applications, August 14--17, 2003.

Boundary conditions for constrained first order symmetric hyperbolic systems, Minnesota PDE Seminar, April 30, 2003.