For a field F with a
p-Henselian valuation v, direct sum decompositions will be proved for Milnor’s
K-theory modn (n a power of the prime p), for the Galois cohomology of F with
Zn-coefficients, and for the graded Witt ring of quadratic forms of F (with p = 2). In
each case, the summands of the ring associated to F are copies of the corresponding
ring associated to the residue field of v, and the number of summands is determined
by its value group. The theorems generalize results known for a field with a complete
discrete valuation.