The simbol is "big O" notation. Shortly it means that the term O(x) has the same order as "x", in the case below, the same ordrer as \delta^3.
Valentin. P.S. see also: http://en.wikipedia.org/wiki/Big_O_notation bipul rakshit wrote: > > Dear Siesta Users, > > I have read the paper > "S. Q. Wang, H. Q. Ye, J. Phys.: Condens. Matter 15 (2003) p. 5307." > > > > Most of the thing is clear to me, except in Equation (7) what is "O(^3)" ? What does 'O' here. > > > Please guide me for the same. > > > Bipul Rakshit > PhD in Physics > Computational Research Lab. > Barkatullah University, > Bhopal 462 026, India > Mob..: +919713445650 > > Yahoo! recommends that you upgrade to the new and safer Internet Explorer 8.
