On logarithmic residue of monogenic functions in a three-dimensional commutative algebra with one-dimensional radical

We consider monogenic functions taking values in a three-dimensional commutative algebra A₂ over the field of complex numbers with one- dimensional radical. We calculate the logarithmic residues of monogenic functions acting from a three-dimensional real subspace of A₂ into A₂. It is shown that the logarithmic residue depends not only on zeros and singular points of a function but also on points at which the function takes values in ideals of A₂, and, in general case, is a hypercomplex number.