# Discrete Logarithm Notation

Im studying for my final, and some of the practice problems that I have found have discrete logarithms in this notation $L_n(p)$.

What does this notation equate to?

For example:

$\log_n(x)$ means the base-$n$ logarithm of $x$. It returns a value $y$ such that $n ^ y = x$.

Since you're working with discrete logarithms, the base will probably be the generator $g$ for your group.

## edit

$L_{13}(x)$ appears to be a shorthand way of writing the above. The only way to find out otherwise would be to consult the notation definitions from the paper (or author) if possible, because it could mean something else entirely or something more specific.

• That being said, this question should probably be on one of the math stackexchanges – Ella Rose Dec 7 '17 at 23:56
• I understand logarithms, but is Ln(x) a shorthand way of writing logn(x)? I asked it in the crypto stackexchange because this notation is in my notes for my cryptography class. – Jeg Dec 7 '17 at 23:58
• @Jeg Do you have an example of it that I can see? It may mean natural logarithm or something else. I probably misunderstood the question. – Ella Rose Dec 7 '17 at 23:59
• I just added the problem that i was reviewing when i saw this notation to the main post – Jeg Dec 8 '17 at 0:03
• @Jeg Thanks I see it now. I don't think that $L_n(x)$ is universally defined to mean anything in particular, you would probably want to check the notation definitions for the paper if possible. Without more information, it looks like $L_{13}(x)$ just means the base-$13$ logarithm of $x$. – Ella Rose Dec 8 '17 at 0:09