Abstract We show that any weakly separated Bessel system of model spaces in the Hardy space on unit disc is a Riesz and we highlight some applications to interpolating sequences matrices. This will be done without using recent solution Feichtinger conjecture, whose natural generalization multidimensional subspaces ${\mathrm {H}}^2$ turns out false.

We say that two permutations $\pi$ and $\rho$ have separated descents at position $k$ if has no before after $k$. give a counting formula, in terms of reduced word tableaux, for computing the structure constants products Schubert polynomials indexed by with descents, recognize these are certain Edelman-Greene coefficients. Our approach uses generalizations Sch\"utzenberger's jeu de taquin algor...