Houjun Liu

logspace

\begin{equation} L = \text{SPACE}\qty(\log n) \end{equation}

For time, the gold standard for languages with \(\geq n\) to read input is \(\text{TIME}\qty(n)\) or at best \(\text{TIME}\qty(n^{k})\).

For space, the gold standard for languages with \(\geq n\) characters is \(\text{SPACE}\qty(\log n)\), because to have pointers, store things, etc., will take this much.

additional information

example

Here are some logspace algorithms.

0 and 1

\begin{equation} A = \qty {0^{m}1^{m}: m \in \mathbb{N}} \end{equation}

palendromes

We can solve it by keeping track of length of input, and then check \(x [i] = x[n-i+1]\)