A NONSYMMETRIC VERSION OF OKOUNKOV’S BC-TYPE INTERPOLATION MACDONALD POLYNOMIALS

Nonsymmetric interpolation Laurent polynomials in n variables are introduced, with the interpolation points depending on q and on a n-tuple of parameters τ = (τ1, …, τn). When τi = stn − 1, Okounkov’s 3-parameter BCn-type interpolation Macdonald polynomials are recovered from the nonsymmetric interpolation Laurent polynomials through Hecke algebra symmetrisation with respect to a type Cn Hecke algebra action. In the Appendix we give some conjectures about extra vanishing, based on Mathematica computations in rank two.

Cascadic Newton’s method for the elliptic Monge–Ampère equation

In this paper, a cascadic Newton’s method is designed to solve the Monge–Ampère equation. In the process of implementing the cascadic multigrid, we use the Full-Local type interpolation as prolongation operator and Newton iteration as smoother. In order to obtain Full-Local type interpolation, we provide several finite difference stencils. Especially, the skewed finite difference methods are first applied by us for the elliptic Monge–Ampère equation. Based on Full-Local interpolation techniques and cascade principle, the new algorithm can save a large amount of computation time. Some numerical experiments are provided to confirm the efficiency of our proposed method.