Math riddles are not only fun but can also be a great source of learning if they help us recall some essential mathematical concepts we learned in school. One such concept was the unitary method, ...

Mathematics of Computation, Vol. 77, No. 261 (Jan., 2008), pp. 353-378 (26 pages) We consider the problem of completion of a matrix with a specified lower triangular part to a unitary matrix. In this ...