# How to denote the space complexity in terms of output

Normally the space complexity of an Algorithm $A$ is denoted $\textrm{SPACE}(A)$, which means how much space is needed by the computation itself. I would however like to also describe how much storage an algorithm needs, i.e. if I have a Turing Machine with three tapes, one for the input, one for the computation, and one for the output, I would like to express the size of each one of them.

Is there a standard way of doing so? If so, is there a reference?

Currently I am using the symbol $\textrm{DATA}$. As an example consider function $list(n) = (1,\dots,n)$. The respective algorithm $List$ for computing the function $list$ is s.t. $\textrm{TIME}(List(n)) \in \mathcal{O}(n)$, since we need to write $n$ symbols, $\textrm{SPACE}(List(n)) = \mathcal{O}(1)$, since we only need to store the current symbol, and $\textrm{DATA}(List(n)) = \mathcal{O}(n)$, since the output is a vector of length $n$.

If your algorithm/TM is called $A$ and the input $x$, it is customary to denote the size of the output by using function and string notation, that is $|A(x)|$.