EN
Let φ:ℝ ² → ℝ be a homogeneous polynomial function of degree m ≥ 2, let μ be the Borel measure on ℝ ³ defined by $μ(E) = ∫_{D} χ_{E}(x,φ(x))dx$ with D = {x ∈ ℝ ²:|x| ≤ 1} and let $T_{μ}$ be the convolution operator with the measure μ. Let $φ = φ₁^{e₁} ⋯ φₙ^{eₙ}$ be the decomposition of φ into irreducible factors. We show that if $e_{i} ≠ m/2$ for each $φ_{i}$ of degree 1, then the type set $E_{μ}: = {(1/p,1/q) ∈ [0,1] × [0,1]: ||T_{μ}||_{p,q} < ∞}$ can be explicitly described as a closed polygonal region.