• Journal of the Chungcheong Mathematical Society
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• v.32 no.1
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• pp.127-138
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• 2019

In this paper, I investigate a stability of the following set-valued functional equation $$f(x+3y){\oplus}10f(x+y){\oplus}7f(-x){\oplus}5f(x-y)=5f(x+2y){\oplus}f(x){\oplus}f(2x){\oplus}f(x-2y)$$ in the sense of P. $G{\check{a}}vruta$.