New algorithms for the numerical solution of optimization problems involving the l 0 pseudo-norm are proposed. They are designed to use a recently proposed computational methodology that is able to deal numerically with finite, infinite and infinitesimal numbers. This new methodology introduces an infinite unit of measure expressed by the numeral x (grossone) and indicating the number of elements of the set IN, of natural numbers. We show how the numerical system built upon x and the proposed approximation of the l 0 pseudo-norm in terms of x can be successfully used in the solution of elastic net regularization problems and sparse Support Vector Machines classification problems.