# Unfamiliar use of interval brackets

• Nov 28th 2013, 05:25 AM
Scurmicurv
Unfamiliar use of interval brackets
Hey, I was wondering if anyone could clear up for me what would generally be meant when you say that a certain value has to

"lie within the strip ] x , y ["? What exactly does it signify when the brackets are in the opposite direction as compared to how you would indicate a closed interval from x to y, [x,y]?
• Nov 28th 2013, 05:36 AM
Plato
Re: Unfamiliar use of interval brackets
Quote:

Originally Posted by Scurmicurv
Hey, I was wondering if anyone could clear up for me what would generally be meant when you say that a certain value has to
"lie within the strip ] x , y ["? What exactly does it signify when the brackets are in the opposite direction as compared to how you would indicate a closed interval from x to y, [x,y]?

That notation is unusual but not unheard of.
$]a,b[=\{x: a,
$]a,b]=\{x: a ,
etc.
• Nov 28th 2013, 05:54 AM
Scurmicurv
Re: Unfamiliar use of interval brackets
Aha, so it's just an open interval? Thanks, that helps a lot to get that cleared up!