Good thing I'm reviewing my #algebra. 'cause I ran into something that is different from when I learned it.

The way I learned it, a closed interval is recorded as [a, b], and an open interval is ]a,b[. I know it looks funky, but it makes total sense... in my head anyway.

However, I'm not seeing open intervals recorded as (a, b).

I looked online and, sure enough, both notations are in use:

https://mathresearch.utsa.edu/wiki/index.php?title=Interval_Notation

I'm not sure if the practice has changed over time, or if it is a feature of the fact that I learned algebra in French.

:catthinking:

Now I feel old and exotic all at once. (Just kidding. :madjoy: )

#math #intervals