Hot answers tagged map
The point is that List has the special property that the head doesn't disappear even with one element. So the solution (as belisarius) noted in the comment is to make the code generate expr with Head List. So that , expr = List[a[i],b[i],c[i],d[i]] Then I can safely pass this to Map as in Map[f, expr], and it doesn't matter how many elements f has. Now ...
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