Recursive set relations
Let \(A(x)\), \(B(x)\), \(C(x)\) be characteristic functions of three measurable sets of real numbers. We determine necessary and sufficient conditions for which \(A(x+ a_n)+ B(x+ b_n)+ C(x+ c_n)= A(x)+ B(x)+ C(x)\) almost everywhere, where \(\{a_n\}\), \(\{b_n\}\), \(\{c_n\}\) are sequences of nonzero shifts approaching zero.
scientific article; zbMATH DE number 2151948