Computation of minimal covariants bases for 2D coupled constitutive laws

We produce minimal integrity bases for both isotropic and hemitropic invariant algebras (and more generally covariant algebras) of most common bidimensional constitutive tensors — possibly coupled laws, including piezoelectricity law, photoelasticity, Eshelby elasticity tensors, complex viscoelasticity tensor, Hill elasto-plasticity, (totally symmetric) fabric up to twelfth-order. The concept covariant, which extends that is explained motivated. It appears be much useful applications. All the tools required obtain these results are in detail a cleaning algorithm formulated achieve minimality case. invariants covariants first expressed forms then tensorial forms, thanks explicit translation formulas provided. proposed approach also applies any n-uplet tensors.