“…A novel formulation for elastoplasticity has been recently developed by Liu (1999a,b, 2000), Liu and Hong (2001), Liu (2001aLiu ( , 2003, and Mukherjee and Liu (2003). These authors have explored the internal symmetry groups of the constitutive models for perfect elastoplasticity with or without considering large rotation, for bilinear elastoplasticity, for visco-elastoplasticity, for isotropic work-hardening elastoplasticity, as well as for mixed-hardening elastoplasticity to ensure that the plastic consistency condition is exactly satisfied at each time step once the computational scheme can take these symmetries into account.…”