Hi, I wanted to use the boost::numeric::interval<T> types for simple arithmetic and elementary functions. I expected them to work out of the box (at least for T=double). However, only arithmetic (+,-,*,/) works. I get name look up errors when I try something like sin(..) or cos(..) of an Interval type. The example with the compiler errors are here: http://codepad.org/4LmWiHiS I tried grepping my global include directory for what the compiler reported it couldn't find (cos_up, cos_down) and the only place it seems to be defined in is: [00:57][~]$ grep -iRl cos_up /usr/include/ /usr/include/boost/numeric/interval/transc.hpp And, including that file doesn't seem to help at all as you can see in the paste. Also on a related note, *none* of the examples here: https://gforge.inria.fr/scm/viewvc.php?view=rev&root=std-interval&sortby=date&revision=5would compile. I expected at least the examples to work out of the box but they don't. Thanks, Chillu