mybgdef.sty

\theoremstyle{definition}
\newtheorem{theorem}{Теорема}[chapter]
\newtheorem{corollary}{Следствие}[chapter]
\newtheorem{lemma}{Лема}[chapter]
\newtheorem{proposition}{Твърдение}[chapter]
\newtheorem{definition}{Определение}[chapter]
\newtheorem{problem}{Задача}[chapter]
\newtheorem{example}{Пример}[chapter]
\newtheorem{question}{Въпрос}[chapter]

\newtheorem*{remark}{Забележка}
\renewenvironment{proof}{\noindent{\bf Доказателство.}\hspace*{1em}}{\qed\par\vspace*{1em}}
\newenvironment{hint}{\noindent{\bf Упътване.}\hspace*{1em}}{\qed\par\vspace*{1em}}
\newenvironment{solution}{\noindent{\bf Решение.}\hspace*{1em}}{\qed\par\vspace*{1em}}