A comparison of arbitrary and symmetric channels on the basis of capacity

This paper concerns itseff with certain upper and lower bounds on the capacity of arbitrary discrete, memoryless channels. A given channel is related to an <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</tex> -ary symmetric channel through a series of operations on the channel matrix, none of which can increase capacity. The bounds are then obtained from the known formula for capacity of a symmetric channel.