What is this "L"-shaped symbol $|\underline{n}$, as in $1+x+x^2/|\underline{2}+x^3/|\underline{3}+\cdots$?

Question

I just got a higher algebra book written by Barnard for a couple bucks. But as I was scrolling through, I found two things that did not make sense. Can anybody tell me the meaning of them (the pic is given below) ? What is that 'L' shaped symbol under the numbers and variables and why is there a limit with "nothing approaching nothing" ?

It seems factorial, but I have never seen any other people writing factorial like this... — Sangchul Lee, Oct 13 '23 at 17:15
https://math.stackexchange.com/questions/1724454/what-is-the-meaning-of-the-symbol-left-underline-n-right-for-integer?noredirect=1&lq=1 — A rural reader, Oct 13 '23 at 17:19

score 3 · Answer 1 · answered Oct 13 '23 at 17:09

3

Given the usage in context, it appears to be factorial. The limit notation is implicitly $\displaystyle\lim_{n\to\infty}.$

answered Oct 13 '23 at 17:09

Chickenmancer

4,347

What is this "L"-shaped symbol $|\underline{n}$, as in $1+x+x^2/|\underline{2}+x^3/|\underline{3}+\cdots$?

1 Answers1