Interval Arithmetic Determinant Evaluation and Its Use in Testing for a Chebyshev System Two recent papers, one by Hansen and one by Hansen and R. R. Smith, have shown how Interval Arithmetic (I.) can be used effectively to bound errors in matrix computations. In the present paper a method proposed by Hasen and R. R. Smith is compared with straightforward use of I. in determinant evaluation. Computational results show the accuracy and running times that can be expected when using I. for determinant evaluation. An application using I. determinants in a program to test a set of functions to see if they form a Chebyshev system is then presented. CACM February, 1969 Smith, L. B. interval arithmetic, range arithmetic, error bounds, determinant evaluation, Chebyshev system, mathematical proof by computer 5.11 5.13 5.14 CA690207 JB February 20, 1978 10:49 AM 1524 4 1931 1931 4 1931 1931 4 1931 1946 4 1931 2214 4 1931 2544 4 1931 1177 5 1931 1931 5 1931 1931 5 1931 1931 5 1931 311 5 1931