  The quasistatic normal-compliance contact problem of isotropic homogeneous
linear visco-elastic bodies with Coulomb friction at small strains in
Kelvin-Voigt rheology is considered. The discretization is made by a
semi-implicit formula in time and the Symmetric Galerkin Boundary Element
Method (SGBEM) in space, assuming that the ratio of the viscosity and
elasticity moduli is a given relaxation-time coefficient. The obtained
recursive minimization problem, formulated only on the contact boundary, has a
nonsmooth cost function. If the normal compliance responds linearly and the 2D
problems are considered, then the cost function is piecewise-quadratic, which
after a certain transformation gets the quadratic programming (QP) structure.
However, it would lead to second-order cone programming in 3D problems.
Finally, several computational tests are presented and analysed, with
additional discussion on numerical stability and convergence of the involved
approximated Poincar\'e-Steklov operators.
