Unconditional optimal H1-norm error estimate and superconvergence analysis of a linearized nonconforming finite element variable-time-step BDF2 method for the nonlinear complex Ginzburg-Landau equation. - Lifang Pei; Yifan Wei 002; Jiwei Zhang 017 (Commun. Nonlinear Sci. Numer. Simul., 2024)