Need continuing counters for different new theorem styles

Question

I'm coding in over leaf and using different new theorem styles. Here's my preamble.

\documentclass[8pt,letterpaper, oneside]{report}
\usepackage{amsmath, amssymb, amscd, amsthm, amsfonts}
\usepackage{graphicx}
\usepackage{hyperref}
\usepackage{enumitem}
\usepackage{tikz-cd}
\oddsidemargin 0pt
\evensidemargin 0pt
\marginparwidth 40pt
\marginparsep 10pt
\topmargin -20pt
\headsep 10pt
\textheight 8.7in
\textwidth 6.65in
\linespread{1.2}
\newtheorem{theorem}{Theorem}[chapter]
\newtheorem{lemma}{Lemma}[chapter]
\newtheorem{conjecture}{Conjecture}[chapter]
\newtheorem{example}{Example}[chapter]
\let\oldexample\example
\renewcommand{\example}{\oldexample\normalfont}
\newtheorem{definition}{Definition}[chapter]
\let\olddefinition\definition
\renewcommand{\definition}{\olddefinition\normalfont}
\newtheorem{proposition}{Proposition}[chapter]
\newtheorem{remark}{Remark}[chapter]
\let\oldremark\remark
\renewcommand{\remark}{\oldremark\normalfont}
\newtheorem{corollary}{Corollary}[chapter]

The problem I am getting is that if I make, say a theorem and a corollary, then they are number Theorem 1 and Corollary 1. How can I display the same counter for all new theorem styles? I mean I would like Theorem 1, Corollary 2, Proposition 3. I don't want a different counter for each newtheorem style.

Welcome to TeX.SE! Please make your code snippet be compilable resulting in your issue, then we do not have to guess what you are doing ... — Mensch, Oct 09 '21 at 14:51
Try \newtheorem{conjecture}[theorem]{Conjecture}\newtheorem{proposition}[theorem]{Proposition}. Have you checked that the document option 8pt has any effect? My guess is that there is a warning in the log file saying that 8pt is unknown and therefore is ignored. Usually there is only the choice between 10pt (default), 11pt, and 12pt. — gernot, Oct 09 '21 at 15:04
Potential duplicate: Understanding the arguments in newtheorem e.g. \newtheorem{theorem}{Theorem}[section] — barbara beeton, Oct 09 '21 at 15:37

score 4 · Accepted Answer · answered Oct 09 '21 at 15:18

Take a look at the documentation of the amsthm package. It provides a solution for several theorem-like environments sharing the same counter, as well as for using different font shapes for the theorem text.

\usepackage{amsthm}
%\theoremstyle{plain}% The default: italic font, extra space above and below theorems 
\newtheorem{theorem}{Theorem}[chapter]
\newtheorem{lemma}[theorem]{Lemma}% use the same counter as theorems
\newtheorem{conjecture}[theorem]{Conjecture}% use the same counter as theorems
\newtheorem{proposition}[theorem]{Proposition}% use the same counter as theorems
\newtheorem{corollary}[theorem]{Corollary}% use the same counter as theorems
\theoremstyle{definition}% upright text, extra space above and below environment
\newtheorem{example}[theorem]{Example}% use the same counter as theorems
\newtheorem{definition}[theorem]{Definition}% use the same counter as theorems
\theoremstyle{remark}% upright text, no extra space above and below
\newtheorem{remark}[theorem]{Remark}% use the same counter as theorems

Need continuing counters for different new theorem styles

1 Answers1