Let p be a rational prime number. We refine Brauer's elementary diagon
alisation argument to show that any system of r homogeneous polynomial
s of degree d, with rational coefficients, possesses a non-trivial p-a
dic solution provided only that the number of variables in this system
exceeds (rd(2))(2d-1). This conclusion improves on earlier results of
Leep and Schmidt, and of Schmidt. The methods extend to provide analo
gous conclusions in field extensions of Q(p), and in purely imaginary
extensions of Q. We also discuss lower bounds for the number of variab
les required to guarantee local solubility.