An Extension of the L a T.pdf

An Extension of the LaTEX theorem environmentFrank MittelbachElectronic Data Systems(Deutschland) GmbHEisenstrae 56D-6090 RusselsheimFederal Republic of GermanyMay 23, 1994AbstractThe macros described in this paper yield an extension of the LaTEXtheorem mechanism. It is designed is to satisfy the dierent requirementsof various journals. Thus, the layout of the \theorems can be manipu-lated by determining a \style. This article describes not only the use,but also the denition, of the necessary macros.Preface to version 2.1This version is identical to 2.0g described in TUGboat 10#3 except for someinternal defaults which are now set depending on the used font selection scheme.This was done to avoid unpleasant surprises if the new font selection schemeis in force. For further details see section 3 and [2, 3].1 IntroductionFor our purposes here, \theorems are labelled enunciations, often set o fromthe main text by extra space and a font change. Theorems, corollaries, conjec-tures, denitions, and remarks are all instances of \theorems. The \header ofthese structures is composed of a label (such as Theorem or Remark) and anumber which serializes an item in the sequence of items with the same label.Shortly after the introduction of LaTEX at the Fachbereich Mathematik inMainz, the desire to manipulate the layout of \theorems arose. In Mainz, thefollowing two conventions came into general use:This le has version number v2.1c, last revised 92/06/22, documentation dated 92/06/22.1 1. The number of the theorem is shown in the margin.2. There is a line break at the end of the theorem header.Additionally, some journals require dierent formats which depend on the\sort of theorem: e.g. often remarks and denitions are set in \rm, while \itis employed for main theorems.Confronted with these requirements, a theorem environment was developedin Mainz which allows separate determination of the layout of the \theoremssets, comparable to \pagestyle.2 The user interface2.1 Dening