Efficient Minkowski sum calculation
===

I wonder whether there is an algorithm to efficiently calculate
a discrete Minkowski sum. The Minkowski sum is defined as:

    S + T = { x + y | x in S, y in T }

Could it be that we can represent the sets as lists, sort S and T, and 
then do something similarly to computing the union of two sets. i.e. walk 
along the sets in parallel and generate the result.

Are such algorithms known where I don't have to additionally sort the
result to remove overlapping cases x1+y1 = x2+y2? Preferably formulated in Java?

