I constantly receive this message, but I do not use the amsmath
package.
/usr/local/texlive/2018/texmf-dist/tex/latex/amsmath/amsmath.sty, line 645
LaTeX Error: Command \iint already defined.
Or name \end... illegal, see p.192 of the manual.
See the LaTeX manual or LaTeX Companion for explanation.
Type H <return> for immediate help.
...
l.645 ...d{\iint}{\DOTSI\protect\MultiIntegral{2}}
Your command was ignored.
Type I <command> <return> to replace it with another command,
or <return> to continue without it.
This is my preamble:
\documentclass[a4paper, 12pt]{article}
\usepackage[utf8]{inputenc}
\usepackage[top=3cm, bottom=2cm, left=3cm, right=2cm]{geometry}
\usepackage{times}
\usepackage[onehalfspacing]{setspace}
\usepackage[T1]{fontenc}
\usepackage[brazil]{babel}
\usepackage{graphicx}
\usepackage{xcolor}
\usepackage{colortbl}
\usepackage{comment}
\usepackage{enumerate}
\usepackage{multirow}
\usepackage{multicol}
\usepackage{indentfirst}
\usepackage{tocbibind}
\usepackage{booktabs}
\usepackage{subfigure}
\usepackage{tikz}
\usepackage{pxfonts}
\usepackage{cancel}
\usepackage{gensymb}
\usepackage{dsfont}
\usepackage{mathtools}
\usepackage{textcomp}
\usepackage[labelfont=bf]{caption}
\usepackage{longtable}
amsmath
itselftimes
andpxfonts
?