  We study the coherent transport in multi-terminal mesoscopic Aharonov-Bohm
ring with a quantum dot embedded in an arm. Employing the Friedel sum rule for
the effective single-particle levels in the quantum dot, we explain some
anomalous features which have been observed in the experiment. We attribute
these anomalies to the result of nontrivial quantum interference of the quantum
dot with the attached ring. Further, we propose a new feature of conductance
oscillations which can be a test for the validity of our model.
