references/addrresses in imperative languages

[Lawrence D’Oliveiro]

In article <1119220461.626477.56110 at g49g2000cwa.googlegroups.com>,
 "Xah Lee" <xah at xahlee.org> wrote:

>A[n] easy way to see this, is to ask yourself: how come in mathematics
>there's no such thing as "addresses/pointers/references".

Yes there are such things in mathematics, though not necessarily under 
that name.

For instance, in graph theory, edges can be considered as "pointers". 
After all, make a change to a node, and that change is visible via all 
edges pointing to that node.