Let f be a homogeneous polynomial with rational coefficients in d variables. We prove several results concerning uniform simultaneous approximation to points on the graph of f , as well as on the hypersurface {f (x 1 , . . . , x d ) = 1}. The results are first stated for the case f (x 1 , . . . , x d ) = x 2 1 + · · · + x 2 d , which is of particular interest.
Diophantine exponentsLet Θ = (θ 1 , . . . , θ m ) be a collection of real numbers. The ordinary Diophantine exponent ω = ω(Θ) for simultaneous rational approximation to Θ is defined as the supremum over all real γ such that the inequality max 1≤j≤m |qθ j − a j | < q −γ 2010 Mathematics Subject Classification: Primary 11J13; Secondary 11J54.