Displaying Mathematical Equations in Web Browsers on the Internet
A Users Viewpoint
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L. David Roper (roperld@vt.edu)
http://arts.bev.net/RoperLDavid
April 2000

Introduction

In my forty years of using computers my maxim has been "Make it simple to use and capable of doing everything." When I was introduced to the Multics computer operating system in the early 1970s, I began to realize that my maxim could possibly come true some day in the dim future. The Macintosh computer interested me until I tried several incarnations of it and realized that it only satisfied the first part of the maxim. Finally, the arrival of Windows 2000 and attendant hardware and software has made the maxim appear inevitable in the near future. I now apply the maxim to the problem of displaying and printing mathematics on the Internet.

Mathematicians and scientists need to have an easy-to-use capability to display mathematical equations in documents on the Internet by means of a web browser. (The two major web browsers are Netscape and Microsoft Internet Explorer.) For a general discussion of how this has been done in the past see Approaches to WWW Mathematics Documents.

In the past the first way to do this was to create the equations in some equation-creating editor (such as MathType), create a graphics file for each equation, and then embed the graphics files in the HyperText Markup Language (HTML) code for the document. (HTML itself does not allow displaying mathematics.) This is very cumbersome, requiring two programs for file creation and the handling of many files. (Other problems with this approach are described in Mathematics on the Web: MathML and MathType.)

T_EX Mathematical Typesetting Program

For the last several decades the standard protocol for creating, display and printing mathematical equations with a computer has been T_EX. For example, the American Mathematical Society has adopted T_EX as its standard for mathematical typesetting.  T_EX files are standard text markup files, which can be created in any text editor.

For several years I have used Scientific Word/WorkPlace as a WYSIWYG editor (SW) for creating T_EX files, as well as a Maple symbolic-mathematics front end (SWP). A non-WYSIWYG specialized T_EX editor is WinTex. One can also use MathType to convert equations to T_EX code and then insert that code into a TeX file.

XML Extensible Markup Language MathML Subset

A major effort is underway to replace HTML with Extensible Markup Language (XML), which has a subset  Mathematical Markup Language (MathML). For excellent discussions of the status of MathML see Mathematics on the Web: MathML and MathType and More Versatile Scientific Documents. There is an Introduction to MathML.

There are various programs that can produce MathML code to be inserted into an HTML document. Some of them are:

• MathType
• WebEQ
• EZMath (see below)
• Amaya (see below)

Apparently, a complete system (a complete WYSIWYG HTML/MathML editor and compatible useable browser) is not yet available for HTML/MathML. MathML capability needs to be incorporated into the major HTML editors (e.g., Microsoft FrontPage and HotMetal) and the two major browsers as a standard feature. There is a specialized browser for MathML, Amaya, but it does not handle well the standard features of web browsers.

EZMath

Another approach to displaying mathematics on the web that is especially easy is EZMath by Hewlett-Packard, which involves a WYSIWYG editor and a browser plug-in that can be downloaded free. The output of the editor is either an object to be embedded in an HTML file or MathML code. There are two major problems with the embedded approach:

• The mathematics in the embedded object is not visible in an HTML editor such as FrontPage.
• The mathematics displayed in the browsers is not printable.

T_EX to the Internet

In the meantime, now that the Internet has become the premier place for fast dissemination of scientific information and since there are already many TeX documents that could be put on the Internet, a method is needed to display TeX documents in the two major web browsers (Netscape and Microsoft Internet Explorer) with a minimum of effort. I know of the following ways to do this:

• After one installs Scientific Word/WorkPlace or the free Scientific Viewer Internet Explorer and Netscape will call the program to display a T_EX file.
• TechExplorer by IBM: This involves a plug-in for the standard browsers that allows them to display a T_EX or MathML file. There is a free version that does not allow printing and a version that does allow printing that costs money. This is not satisfactory, because one wants mathematics documents capable of being read and printed by anyone without any cost for extra software. If printing were allowed for the free download, this might be a good approach.
• T_TH is a free TeX to HTML translator, which uses tables and browser fonts to render the equations. Multi-layered equations are not very good. There is a commercial version called TeX2HTML.
• TtM is a DOS TeX to MathML translator. Of course, one then needs a MathML plug-in for browsers.
• Publicon is a WYSIWYG mathematics publishing system that can import or export T_EX, HTML or MathML files. It is in the demonstration phase now, which I have used. The current free demonstration version (version 0.9) does not create T_EX or MathML files, but the first commercial version (version 1.0) is slated to both import and export T_EX and MathML files. Publicon has the capability of web links; one hopes that capability will be transferred to the created MathML files.
• Portable Document Format (PDF) by Adobe Systems: One can, for example, print to PDF Writer within Scientific Word/WorkPlace (SWP). (PDF files can be viewed in a standard browser by downloading the free Adobe Acrobat Reader.) Then one can use Adobe Acrobat to create web links within the PDF file. SWP has web-links capability, but the links are not transferable to the PDF file. If the SWP web links could be transferred to a PDF file, this would be an good approach. As it is now, this makes it hard to make changes in a file with links after it is put on the web.

Occasionally for math documents with no Internet links I use the last of these options to convert T_EX documents into PDF documents to view on the web. I create the documents with Scientific Word/WorkPlace and create the PDF file by printing to PDF Writer.

In the near future I will use Scientific Word/WorkPlace to create all math documents to be put on the Internet. At the link site I will inform the user that she/he can download the free Scientific Viewer to view the document from within the browser.

Conclusion

To be able to easily produce mathematical documents that anyone can read and print on the Internet the following are needed:

1. A WYSWYG full word processor with mathematics formatting capability that can produce MathML and T_EX files with web links. Scientific Word/WorkPlace produces T_EX files which can be viewed from within a browser with the free Scientific Viewer. I am told that it will produce MathML files in the future. It appears that Publicon will satisfy this when it finally is released. One hopes that its price will be reasonable, so that it can be widely used.
2. Viewing capabilities in the standard browsers for MathML and T_EX files with web links, without any plug-ins added. If this is not possible, then free full-capability plug-ins are needed for the standard browsers. One can view T_EX files now with the free Scientific Viewer.

The T_EX read/print capability is needed, as well as MathML capability, because a huge inventory of T_EX files already exists.