“…Such equations have been studied by many authors on various situations, for example, on spaces of holomorphic functions on convex domains, those with growth conditions near the boundary, hyperfunctions, Fourier hyperfunctions, etc. See Hörmander [7], Korobeȋnik [11], Kawai [12], Ishimura-Okada [10], Abanin-Ishimura-Khoi [1], Langenbruch [13] and the references therein. Necessary or sufficient conditions for solvability are often written in terms of the Fourier (or Laplace) transform of the kernel.…”