A (positive definite and integral) quadratic form f is said to be universal if it represents all positive integers, primitively integers primitively. We also say almost Conway Schneeberger proved (see [1]) that there are exactly 204 equivalence classes of quaternary forms. Recently, Earnest Gunawardana in [4] among forms, 152 In this article, we prove 107 determine the set not represented by ea...

We present algorithms for square classes, quadratic forms and Witt classes of quadratic forms over the eld of rational functions of one variable over the reals. The algorithms are capable of: nding the unique representative of a square class, deciding if a given function is a square or a sum of squares and deciding if a quadratic form is isotropic or hyperbolic. Moreover we propose a representa...