<html><head><meta name="color-scheme" content="light dark"></head><body><pre style="word-wrap: break-word; white-space: pre-wrap;">\section{\texorpdfstring{Giá»›i thiá»‡u. Ghi chÃº}{Gioi thieu. Ghi chu}}

%% For our purposes here, ``theorems'' are labelled enunciations,
%% often set off from the main text by extra space and a font change.
%% Theorems, corollaries, conjectures, definitions, examples, 
%% remarks, and proofs are all instances of ``theorems''.  
%% The ``header'' of 
%% these structures is composed of the type of the structure 
%% (such as \textsc{Theorem} or \textsc{Remark}), a number 
%% which serializes the instances of the same type throughout the
%% document, and an optional name (such as ``Correctness Theorem'').
Má»™t mÃ´i trÆ°á»ng tá»±a Ä‘á»‹nh lÃ½, ta gá»i táº¯t lÃ&nbsp; (mÃ´i trÆ°á»ng) |THM|,
Ä‘Æ°á»£c minh há»a nhÆ° á»Ÿ HÃ¬nh~\vref{fig:THM}.
Vá»›i má»—i |THM|, cÃ¡c tÃªn |Ä‘á»‹nh lÃ½|, |há»‡ quáº£|, |bá»• Ä‘á»|, |tiÃªn Ä‘á»|,
|Ä‘á»‹nh nghÄ©a|, |vÃ­ dá»¥|, |ghi chÃº|, |chá»©ng minh|,\ldots
Ä‘Æ°á»£c gá»i lÃ&nbsp; \emph{tÃªn cá»§a} |THM|.
Pháº§n |header| cá»§a |THM| bao gá»“m tÃªn cá»§a |THM|, chá»‰ sá»‘ cá»§a |THM|,
tÃªn tuá»³ chá»n (hay tÃªn riÃªng) cá»§a |THM|. Pháº§n ná»™i dung cá»§a |THM|
cÃ²n gá»i lÃ&nbsp; \emph{thÃ¢n} (|body|) cá»§a |THM|. Äá»ƒ Ã½ ráº±ng, tÃªn cá»§a |THM| khÃ¡c
vá»›i tÃªn cá»§a mÃ´i trÆ°á»ng |THM|.\footnote{Trong thá»±c táº¿, thÆ°á»ng tÃªn
cá»§a mÃ´i trÆ°á»ng \texttt{THM} vÃ&nbsp; tÃªn cá»§a \texttt{THM} cÃ³ sá»± tÆ°Æ¡ng á»©ng
1-1, vÃ­ dá»¥ \texttt{menhde} á»©ng vá»›i \texttt{Má»‡nh Ä‘á»},
\texttt{dinhly} á»©ng vá»›i \texttt{Äá»‹nh lÃ½}. Do Ä‘Ã³, trong Ä‘a sá»‘ trÆ°á»ng há»£p,
sá»± phÃ¢n biá»‡t nÃ&nbsp;y khÃ´ng cÃ³ Ã½ nghÄ©a quan trá»ng\ldots --- kyanh}
Trong vÃ­ dá»¥ sau,
\begin{example}
  \newtheorem{foobar}{Menh de}
\end{example}
ta cÃ³ |THM| |foobar|, vá»›i tÃªn lÃ&nbsp; |Menh de|, nhÆ°ng tÃªn cá»§a mÃ´i trÆ°á»ng
tÆ°Æ¡ng á»©ng lÃ&nbsp; |foobar|. ÄÃ´i khi, ta sáº½ gá»i \emph{mÃ´i trÆ°á»ng} |THM| thay cho
\emph{tÃªn cá»§a mÃ´i trÆ°á»ng} |THM|.
%% dÃ¹ng Ä‘á»ƒ chá»‰ loáº¡i cá»§a cáº¥u trÃºc (vÃ­ dá»¥ Ä‘á»‹nh lÃ½ hay
%% Ä‘á»‹nh nghÄ©a), chá»‰ sá»‘ cá»§a cáº¥u trÃºc vÃ&nbsp; tÃªn tuá»³ chá»n (vÃ­ dá»¥ |TiÃªn Ä‘á» chá»n|).
%% CÃ¡c (tá»±a) Ä‘á»‹nh lÃ½ thÆ°á»ng pháº£i Ä‘Æ°á»£c trÃ¬nh bÃ&nbsp;y rÃµ rÃ&nbsp;ng, tÃ¡ch biá»‡t
%% vá»›i cÃ¡c pháº§n khÃ¡c cÃ¹a tÃ&nbsp;i liá»‡u, báº±ng cÃ¡ch thÃªm cÃ¡c khoáº£ng tráº¯ng
%% thÃ­ch há»£p, thay Ä‘á»•i kiá»ƒu chá»¯. 

%% The layout of theorems can be changed by parameters as the fonts
%% of the header and the body, the way how to arrange the headers,
%% the indentation, and the way of numbering it.
%% Confronted with these requirements, |theorem.sty|, a style for 
%% dealing with theorem layout was developed by Frank Mittelbach
%% which was the standard theorem-environment for long time.
\medskip
CÃ¡ch thá»ƒ hiá»‡n |THM| cÃ³ thá»ƒ Ä‘Æ°á»£c thay Ä‘á»•i nhá» cÃ¡c tham sá»‘ vá»
kiá»ƒu chá»¯ cho |header|, cho thÃ¢n |THM|, cÃ¡c bá»‘ trÃ­ |header|, khoáº£ng tráº¯ng
thá»¥t Ä‘áº§u dÃ²ng, cÃ¡ch Ä‘Ã¡nh sá»‘,\ldots Äá»ƒ thá»a mÃ£n cÃ¡c yÃªu cáº§u thay Ä‘á»•i nÃ&nbsp;y,
gÃ³i |theorem.sty| cá»§a Fran Mittelbach Ä‘Ã£ Ä‘Æ°á»£c viáº¿t vÃ&nbsp; trá»Ÿ thÃ&nbsp;nh
gÃ³i chuáº©n cá»§a \LaTeX{} tá»« ráº¥t lÃ¢u.

%% But then the desire for additional features like ``endmarks''
%% and ``theorem-lists'' arose. 
%% Two extensions of |theorem.sty| were developped: One for handling 
%% endmarks, |thmmarks.sty| and one for generating lists, |newthm.sty|. 
%% Thus, Frank Mittelbach suggested to combine the new features into 
%% one ``standard-to-be'' package. 
%% And now, here it is.
\medskip
Tuy nhiÃªn, cÃ¡c tÃ­nh nÄƒng khÃ¡c nhÆ°ng dáº¥u káº¿t thÃºc |endmarks|, danh sÃ¡ch
cÃ¡c |theorem| váº«n chÆ°a Ä‘Æ°á»£c há»— trá»£ bá»Ÿi gÃ³i chuáº©n Ä‘Ã³. Giáº£i quyáº¿t váº¥n Ä‘á» nÃ&nbsp;y,
cÃ³ hai má»Ÿ rá»™ng cá»§a gÃ³i |theorem.sty| Ä‘Æ°á»£c phÃ¡t triá»ƒn: má»™t gÃ³i chuyÃªn vá»
Ä‘iá»u khiá»ƒn |endmarks|, gÃ³i |thmmarks.sty|, vÃ&nbsp; má»™t gÃ³i chuyÃªn vá» liá»‡t
kÃª danh sÃ¡ch |THM|, gÃ³i |newthm.sty|. Sau Ä‘Ã³, Frank Mittelbach Ä‘á» nghá»‹
káº¿t há»£p cÃ¡c há»— trá»£ cá»§a hai gÃ³i nÃ&nbsp;y vÃ&nbsp;o cÃ¹ng má»™t gÃ³i má»›i (sáº½ lÃ&nbsp; chuáº©n).
ÄÃ³ chÃ­nh lÃ&nbsp; gÃ³i |ntheorem.sty| ;)

\begin{figure}[bht]
\begin{center}
	\ifpdf
		\includegraphics[scale=.6]{thm.png}
	\else
		\includegraphics[scale=.6]{thm.ps}
	\fi
\end{center}
\caption{MÃ´i trÆ°á»ng THM}
\label{fig:THM}
\end{figure}

\endinput
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