I have a function for which 0 is a special case: f[A___, 0, B___] := 0 But since I am doing numerics, sometimes in the course ...
I would like a table with rational indexes - thus it would be practical to use a dictionary, which, in Mathematica are implemented with the indexed variables. I would like to be able to do: ...
How can I clear a subset of a symbol's DownValues ? For example, suppose I have created some DownValues for $f$ like this: ...
Mathematica has a notion of pattern specificity, which is a partial ordering on patterns. The rules (e.g. DownValues, ...