Article
Keywords:
Birkhoff interpolation; Pell equation
Summary:
Finding the normal Birkhoff interpolation schemes where the interpolation space and the set of derivatives both have a given regular ``shape'' often amounts to number-theoretic equations. In this paper we discuss the relevance of the Pell equation to the normality of bivariate schemes for different types of ``shapes''. In particular, when looking at triangular shapes, we will see that the conjecture in Lorentz R.A., {\it Multivariate Birkhoff Interpolation\/}, Lecture Notes in Mathematics, 1516, Springer, Berlin-Heidelberg, 1992, is not satisfied, and, at the same time, we will describe the complete solution.
References:
[2] Lorentz R.A.:
Multivariate Birkhoff Interpolation. Lecture Notes in Mathematics, 1516, Springer, Berlin-Heidelberg, 1992.
MR 1222648 |
Zbl 0760.41002
[4] Stillwell J.:
Elements of number theory. Undergraduate Texts in Mathematics, Springer, New York, 2003.
MR 1944957 |
Zbl 1112.11002