We prove an asymptotical formula for the number of representations
of a given monic polynomial ƒ ∈ Ζ[x] by the sum of

monic irreducible polynomials in Ζ[x] whose heights are bounded
by

. The main term turns out to be

,
where

and

is some positive rational number.
The binary case

was first considered by Hayes in 1965 as a
version of a binary Goldbach problem for polynomials. In this
case, we improve the error term in a recent asymptotical formula
(due to Kozek) and show that our error term is best possible for
each

.