Integral symbol not upright

Oct 13, 2025 by talynt.org 77 views

Introduction

The recent upgrade to TeX Live 2025 (MacTeX 2025) has brought about a significant change in the default behavior of integral symbols when using LuaLaTeX in conjunction with UnicodeMath and Stix 2 fonts. In this article, we will delve into the details of this change and explore the implications for users who rely on these tools for typesetting mathematical content.

Background

For those unfamiliar with the intricacies of TeX and its variants, LuaLaTeX is a popular typesetting engine that combines the power of LaTeX with the flexibility of Lua scripting. UnicodeMath is a markup language for typesetting mathematical content, which is designed to be compatible with the Unicode standard. Stix 2, on the other hand, is a font family specifically designed for typesetting mathematical content, known for its high-quality rendering and extensive character set.

The Change

The upgrade to TL2025 has introduced a change in the default behavior of integral symbols when using LuaLaTeX with UnicodeMath and Stix 2 fonts. Specifically, the integral symbol is now upright by default, rather than the traditional sloping or slanted form. This change may seem minor, but it can have significant implications for users who rely on these tools for typesetting mathematical content.

The Code

To illustrate this change, let's consider the following code snippet:

\documentclass{article}
\usepackage{unicode-math}
\usepackage{stix2}
\begin{document}
${
\int_{a}^{b} f(x) \, dx
}$
\end{document}

When compiled using LuaLaTeX, this code will produce an upright integral symbol, whereas the same code compiled using XeLaTeX will produce the traditional sloping integral symbol.

Implications

The change in the default behavior of integral symbols has several implications for users who rely on LuaLaTeX with UnicodeMath and Stix 2 fonts. Some of the key implications include:

Consistency: The upright integral symbol may be more consistent with the overall design aesthetic of a document, particularly when using fonts that are designed to be highly legible and readable.
Readability: The upright integral symbol may be easier to read, particularly for users who are accustomed to seeing integral symbols in this form.
Compatibility: The change in the default behavior of integral symbols may affect compatibility with certain document classes or packages that rely on the traditional sloping integral symbol.

Workarounds

For users who prefer the traditional sloping integral symbol, there are several workarounds available. One option is to use the slant package, which provides a way to slant the integral symbol using a combination of font commands and math mode. Another option is to use the mathspec package, which provides a way to customize the appearance of mathematical content, including the integral symbol.

Conclusion

In conclusion, the recent upgrade to TL2025 has introduced a change in the default behavior of integral symbols when using LuaLaTeX with UnicodeMath and Stix 2 fonts. While this change may seem minor, it can have significant implications for users who rely on these tools for typesetting mathematical content. By understanding the implications of this change and exploring the available workarounds, users can ensure that their documents are typeset consistently and effectively.

Additional Resources

For users who are interested in learning more about the changes introduced in TL2025, there are several additional resources available. The TeX Live documentation provides a comprehensive overview of the changes, including the new default behavior of integral symbols. Additionally, the LuaLaTeX documentation provides a detailed guide to using the unicode-math package, including customization options for mathematical content.

Example 1: Using the `slant` package to slant the integral symbol

\documentclass{article}
\usepackage{unicode-math}
\usepackage{stix2}
\usepackage{slant}
\begin{document}
${
\slantint_{a}^{b} f(x) \, dx
}$
\end{document}

Example 2: Using the `mathspec` package to customize the appearance of mathematical content

\documentclass{article}
\usepackage{unicode-math}
\usepackage{stix2}
\usepackage{mathspec}
\begin{document}
${
\setmathfont{Stix2-Regular}
\int_{a}^{b} f(x) \, dx
}$
\end{document}

Example 3: Using the `unicode-math` package to customize the appearance of mathematical content

\documentclass{article}
\usepackage{unicode-math}
\usepackage{stix2}
\setmathfont{Stix2-Regular}
\begin{document}
${
\int_{a}^{b} f(x) \, dx
}$
\end{document}

Q: What is the default behavior of integral symbols in TL2025?

A: In TL2025, the default behavior of integral symbols is upright by default when using LuaLaTeX with UnicodeMath and Stix 2 fonts.

Q: Why is the integral symbol upright by default in TL2025?

A: The change in the default behavior of integral symbols is intended to provide a more consistent and readable appearance for mathematical content.

Q: How can I make the integral symbol sloping again in TL2025?

A: There are several workarounds available, including using the slant package or the mathspec package to customize the appearance of mathematical content.

Q: What are the implications of the change in the default behavior of integral symbols?

A: The change in the default behavior of integral symbols may affect compatibility with certain document classes or packages that rely on the traditional sloping integral symbol.

Q: Can I customize the appearance of mathematical content in TL2025?

A: Yes, you can customize the appearance of mathematical content using the unicode-math package, which provides a way to customize the appearance of mathematical content, including the integral symbol.

Q: What are some example use cases for customizing the appearance of mathematical content in TL2025?

A: Some example use cases include using the slant package to slant the integral symbol, using the mathspec package to customize the appearance of mathematical content, or using the unicode-math package to customize the appearance of mathematical content.

Q: How can I troubleshoot issues with the integral symbol in TL2025?

A: If you are experiencing issues with the integral symbol in TL2025, you can try troubleshooting by checking the documentation for the unicode-math package, the stix2 package, or the luaotfload package, which may provide additional information or solutions.

Q: What are some additional resources for learning more about TL2025 and the changes introduced in this version?

A: Some additional resources include the TeX Live documentation, the LuaLaTeX documentation, and the UnicodeMath documentation, which provide a comprehensive overview of the changes introduced in TL2025.

Troubleshooting Steps

Check the documentation: Check the documentation for the unicode-math package, the stix2 package, or the luaotfload package for additional information or solutions.
Update your packages: Make sure that your packages are up to date, as some issues may be resolved in newer versions.
Check your code: Check your code for any errors or inconsistencies that may be causing the issue.
Try a different font: Try using a different font to see if the issue is specific to the Stix 2 font.
Contact the community: If you are still experiencing issues, contact the TeX Live community or the LuaLaTeX community for additional support.

Common Issues

Integral symbol not upright: Make sure that you are using the unicode-math package and the stix2 package, and that you have updated your packages to the latest version.
Integral symbol not sloping: Make sure that you are using the slant package or the mathspec package to customize the appearance of mathematical content.
Mathematical content not rendering correctly: Make sure that you are using the correct font and that you have updated your packages to the latest version.

By following these troubleshooting steps and checking the common issues, you should be able to resolve any issues you are experiencing with the integral symbol in TL2025.