Problems with amsmath

Question

This is my premble to a document and I always get the error LaTeX Error: C ommand \iint already defined.

\RequirePackage{fix-cm}
%
\documentclass{svjour3}                     % onecolumn (standard format)
%
%\smartqed  % flush right qed marks, e.g. at end of proof
%
\usepackage{graphicx}
\usepackage{hyperref}
\usepackage{caption}
\usepackage{array}
\usepackage{xfrac}
\usepackage{enumitem}
\usepackage{wasysym}
\usepackage{multirow}
\usepackage{amsmath}`

What can I do? Where is the conflict?

Answer 1

The package wasysym should be loaded after amsmath and be passed the option nointegrals (unless you really want the multiple integral symbols in wasysym to take over).

\RequirePackage{fix-cm}
%
\documentclass{svjour3}                     % onecolumn (standard format)
%
%\smartqed  % flush right qed marks, e.g. at end of proof
%
\usepackage{graphicx}
\usepackage{caption}
\usepackage{array}
\usepackage{xfrac}
\usepackage{enumitem}
\usepackage{multirow}
\usepackage{amsmath}
\usepackage[nointegrals]{wasysym}
\usepackage{hyperref}

Note that hyperref should be loaded last.

From the manual of wasysym:

Actually, the loading order is relevant, as you discovered.

Answer 2

If you add (and uncomment) \show commands as I have below, it is easy to see the point at which the commands become defined, in this case wasysym. You can \let them to \relax to undefine them then amsmath will give its definitions

\RequirePackage{fix-cm}
%
\documentclass{svjour3}                     % onecolumn (standard format)
%
%\smartqed  % flush right qed marks, e.g. at end of proof
%
\usepackage{graphicx}
\usepackage{hyperref}
\usepackage{caption}
\usepackage{array}
\usepackage{xfrac}
\usepackage{enumitem}
%\show\iint
\usepackage{wasysym}
%\show\iint
\let\iint\relax
\let\iiint\relax
\usepackage{multirow}
%\show\iint
\usepackage{amsmath}
%\show\iint