A characterization of compactly supported orthonormal wavelets (Q1335003)

The construction of orthogonal wavelets via scaling equations suffers from a notorious drawback: sufficient conditions for orthogonality (Cohen's criterion, eigenspaces of Lawton's matrix) cannot be stated explicitly in terms of the scaling coefficients. The author proves a new sufficient condition, which only requires to check whether the determinant of a related matrix is non-zero. This elegant result closes a gap in the description of wavelets via scaling equations.