2004-Fez conference on Differential Equations and Mechanics. Electronic Journal of Differential Equations, Conference 11, 2004, pp. 23-32. Title: On the well-posedness of the heat equation on unbounded domains Authors: Wolfgang Arendt (Univ. Ulm, Germany) Soumia Lalaoui Rhali (Univ. Sidi Mohamed Ben Abdellah, Morocco) Abstract: This work concerns the well-posedness of the heat equation in an unbounded open domain, under basic regularity assumptions on this domain. Published October 15, 2004. Math Subject Classifications: 35K05, 35K20, 47D06. Key Words: Unbounded domains; heat equation; Dirichlet problem; resolvent positive operators.