# What are {} and [] functions?

I see these functions in Bondy-Murty book about graph theory...

In book written: "The complete m-partite graph on n vertices in which each part has either [n/m] or {n/m} vertices is donated by T m,n. Show that..."

Can someone explain me what are these functions?

• The book has a section on notation, right? Sep 25, 2014 at 18:54
• Do the floor and ceiling functions $\lfloor{n/m}\rfloor$ and $\lceil{n/m}\rceil$ make sense in context? I've seen $[n/m]$ used to denote the former before, though $\{n/m\}$ often denotes the fractional part of $n/m$. Sep 25, 2014 at 18:55

As a general rule, just look at the section on notation in your book:

• I don't know that the book has a "Glossary of Symbols" :D Thanks "Hakim" Sep 25, 2014 at 19:08
• @user3178448 But you could have known.
– MJD
Sep 25, 2014 at 19:08
• @user3178448 You're welcome, keep in mind that most textbooks have a glossary of symbols. Sep 25, 2014 at 19:08
• I'm very beginner in math and this is my first English math book ... Sep 25, 2014 at 19:10

$[n/m]$ means greatest integer function(or floor function), i.e. an integer $k$ s.t. $[n/m]-1<k\leq [n/m]$

and {n/m} means ceiling function i.e. an integer $k$ s.t. {n/m}$\leq k<${n/m}+1.

For example, [$5/2=2.5]=2$ and {$5/2=2.5$}=$3$