Fourth Lecture

Abstract

We will now continue with prefix operators provided by Reduce. Some of these operators, after evaluation, return more than one value. Those values are put into a list, which is a set of elements enclosed by two curly brackets¹. The elements may be expressions or again lists:

$$ \{ el1,el2,el3,el4\} $$

$$ \{ a*(b + c)**4,\{ nothing\}, \{ y,n,g,q\} \} $$

Some operators even take lists as arguments. Hence it is necessary to have operators at one’s disposal which extract single expressions out of a list or which can combine lists and the like.