The functional equationย ๐(๐ฅ+๐ฆ) - ๐(๐ฅ) - ๐(๐ฆ) = ๐(๐ฅ, ๐ฆ) has a solutionย ๐ that belongs to C0(โ) if and only if the symmetric cocycle ๐ belongs toย C0(โ2). If the symmetric cocyleย ๐ is recursively approximable, there exists a solutionย ๐ which is recursively approximable also. Ifย ๐ belongs toย C1(โ2) then there exists an integral expression in ๐ for a solutionย ๐ that belongs toย C1(โ), and the same happens for the classes Ck, Cโ, analytic and polynomial.
@article{1586, title = {Concrete algebraic cohomology for the group (R, +) or how to solve the functional equation f(x+y) - f(x) - f(y) = g(x, y)}, journal = {CUBO, A Mathematical Journal}, volume = {9}, year = {2007}, language = {en}, url = {http://dml.mathdoc.fr/item/1586} }
Prunescu, Mihai. Concrete algebraic cohomology for the group (โ, +) or how to solve the functional equation ๐(๐ฅ+๐ฆ) - ๐(๐ฅ) - ๐(๐ฆ) = ๐(๐ฅ, ๐ฆ). CUBO, A Mathematical Journal, Tome 9 (2007) . http://gdmltest.u-ga.fr/item/1586/