This paper deals with the formulation, implementation, and application of p
otentially powerful temporal finite element approximations for solving init
ial value problems. Weighted residual methods using continuous and disconti
nuous approximations are developed and their characteristics in terms of ac
curacy and stability are presented and discussed. An adaptive time spectral
element methodology is proposed for Lagrangian spectral elements and its c
omputational performance is demonstrated for stiff systems of ordinary diff
erential equations. (C) 2000 IMACS. Published by Elsevier Science B.V. All
rights reserved.