svmono template and `\mathcal`

Question

Why, with Springer's svmono template, do the letters written with the \mathcal font change? It seems that \mathcal becomes \mathscr.

Edit: Look at this image:

With the svmono template \mathcal returns the first alphabet and not the (classical) latter.

Here the packages I use in my document:

\documentclass[envcountsame,envcountchap]{svmono} 
\usepackage{subfiles}
\usepackage[utf8]{inputenc} 
\usepackage{mathptmx}
\usepackage[bottom]{footmisc}
\usepackage{microtype}
\usepackage{stmaryrd}   
\usepackage{amsmath}
\usepackage{courier}
\usepackage{mathrsfs} 
\usepackage{amssymb} 
\usepackage[all,cmtip]{xy}
\usepackage{faktor}
\usepackage{graphicx}
\usepackage{mathdots}
\usepackage[colorlinks={true},linkcolor={blue},citecolor={blue}]{hyperref}
\usepackage[frame,width=15truecm,height=23.5truecm,center]{crop}

With this settings I have the above strange behavior of \mathcal.

Answer 1

The mathptmx package draws its calligraphic letters from the RSFS font, which explains the behavior you get, which has nothing to do with the svmono class.

Minimal example:

\documentclass{article}
\usepackage{mathptmx}
\begin{document}
$\mathcal{ABCDEF}$
\end{document}

If you want to reinstate the Computer Modern calligraphic letters, add

\DeclareMathAlphabet{\mathcal}{OMS}{cmsy}{m}{n}

to your preamble.