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K. Baron and Z. Kominek [2] have studied the functional inequality f(x + y) - f(x) - f(y) is less than or equal [phi](x, y), x, y is an element of X, under the assumptions that X is a real linear space, (phi] is homogeneous with respect to the second variable and f satisfies certain regularity conditions. In particular, they have shown that [phi] is bilinear and symmetric and f has a representation...