However, because DSTs operate on "finite", "discrete" sequences, two issues arise that do not apply for the continuous sine transform. First, one has to specify whether the function is even or odd at "both" the left and right boundaries of the domain (i.e. the min-"n" and max-"n" boundaries in the definitions below, respectively). Second, one has to specify around "what point" the function is even or odd. In particular, consider a sequence ("a","b","c") of three equally spaced data points, and say that we specify an odd "left" boundary. There are two sensible possibilities: either the data is odd about the point "prior" to "a", in which case the odd extension is (−"c",−"b",−"a",0,"a","b","c"), or the data is odd about the point "halfway" between "a" and the previous point, in which case the odd extension is (−"c",−"b",−"a","a","b","c")