Two-step Bdf Time Discretisation of Nonlinear Evolution Problems Governed by Monotone Operators with Stringly Continuous Peryurbations

The time discretisation of the initial-value problem for a first-order evolution equation by the two-step backward differentiation formula (BDF) on a uniform grid is analysed. The evolution equation is governed by a time-dependent monotone operator that might be perturbed by a time-dependent strongly continuous operator. Well-posedness of the numerical scheme, a priori estimates, convergence of a piecewise polynomial prolongation, stability as well as smooth-data error estimates are provided relying essentially on an algebraic relation that implies the G-stability of the two-step BDF with constant time steps. 2000 Mathematics Subject Classification: 65M12, 65M15, 47J35, 35K55, 47H05.