  This overview provides an interface between lines of thought on rfi
mitigation in the fields of radio astronomy and signal processing. The goal is
to explore the commonality of different approaches to help researchers in both
fields interpret each others' concepts and jargon. The paper elaborates on the
astronomers' concept of gain closure relations and how they may be used in a
"self-calibrating" system of rfi cancellation. Further discussion of the eigen
decomposition method in terms of rfi power and antenna gains introduces
adaptive nulling and rfi cancellation through matrix partitioning. While
multipath scattering appears at first glance to be fatal to methods of rfi
cancellation, its effect is easily incorporated in frequency dependent gain
coefficients under many circumstances.
