A note on Babylonian square-root algorithm and related variants.
Let be a field. We compute the set ofnaivehomotopy classes of pointed -scheme endomorphisms of the projective line . Our result compares well with Morel’s computation in [11] of thegroup of -homotopy classes of pointed endomorphisms of : the set admits an a priori monoid structure such that the canonical map is a group completion.
Using the principle that characteristic polynomials of matrices obtained from elements of a reductive group over typically have splitting field with Galois group isomorphic to the Weyl group of , we construct an explicit monic integral polynomial of degree whose splitting field has Galois group the Weyl group of the exceptional group of type .