MathML namespace declaration in .css not "sticking"

wanderson · 03-04-2025, 10:25 AM

I'm editing a equation-heavy epub and I'm using a lot of MathML markups. I'd like for the text to be as economical as possible, so I'd like to avoid this kind of tag:

Code:

<math xmlns="http://www.w3.org/1998/Math/MathML"> ... </math>

and instead use a single namespace declaration in the stylesheet.css, namely:

Code:

@namespace math url(http://www.w3.org/1998/Math/MathML);

which would (theoretically) enable a simpler MathML tag:

Code:

<math> ... </math>

This doesn't seem to be working for me in the Calibre editor / previewer. It may be the case that the namespace is conveyed to the first instance of a <math> tag in a file, but the remaining tags "forget" the namespace designation.

What am I doing wrong? Thanks in advance for any help.

kovidgoyal · 03-04-2025, 12:17 PM

namespace declarations in CSS do not change the namespace of tags in html. They just allow css tag based selectors to use namespaces.

wanderson · 03-04-2025, 12:33 PM

Quote:

Originally Posted by kovidgoyal

namespace declarations in CSS do not change the namespace of tags in html. They just allow css tag based selectors to use namespaces.

So, is there no concise way to have all the <math> tags in a file use a given namespace?

DNSB · 03-04-2025, 06:39 PM

Have you tried modifying the <html> tag at the start of each XHTML file to read:

Code:

<html xmlns="http://www.w3.org/1999/xhtml" xmlns:epub="http://www.idpf.org/2007/ops" xmlns:math="http://www.w3.org/1998/Math/MathML">

I haven't done much with books containing MathML but I've seen that structure in a couple of them.

The attached file seems to display happily in Sigil but not in calibre's ebook-editor.

wanderson · 03-07-2025, 03:49 PM

Quote:

Originally Posted by DNSB

Have you tried modifying the <html> tag at the start of each XHTML file to read:

Code:

<html xmlns="http://www.w3.org/1999/xhtml" xmlns:epub="http://www.idpf.org/2007/ops" xmlns:math="http://www.w3.org/1998/Math/MathML">

I haven't done much with books containing MathML but I've seen that structure in a couple of them.

The attached file seems to display happily in Sigil but not in calibre's ebook-editor.

Thanks, DNSB, but I've found out that even in Sigil (and certainly in Calibre's ebook editor preview pane), this doesn't distribute to all the <math> blocks in the file, only the first. The namespace designation must be appended to each block, alas. I therefore consider this matter closed and will do it the verbose way.

DNSB · 03-07-2025, 03:57 PM

Sounds like a job for a clip.

KevinH · 03-07-2025, 06:12 PM

That Sigil ignores that namespace makes no sense. Adding the mathml namespace prefix "math" to the html tag and then using that prefix "math" for each math tag in the file (ie. each tag becomes math:math) should work. That is what namespace prefixes are for.

More importantly though math tags do NOT need a prefix at all under the html5 xhtml variant used for epub3 according to the spec. The math tag and its contents is autorecognized as a foreign tag (just like the svg tag) and modern parsers should understand it just fine without the need for declaring any namespace prefix for it.

Have you tried without any specific namespace prefix defined for mathml at all?

I wonder if this is a limitation of Qt6's webengine's new built in mathml support in some way?

Update: It is not. To test with Sigil I opened an epub full of mathml and did a global find and replace to remove all of the math tag namespace declarations that said no prefix needed:

ie:
xmlns="http://www.w3.org/1998/Math/MathML"

and made sure no mathml prefix namespace was defined on the html tag.

And sure enough no parsing errors or problems at all. All equations looked as expected.

So no math namespace prefix need be defined and no xmlns="http://www.w3.org/1998/Math/MathML" need be added to math tags as it is properly namespaced by the parser under the html5 xhtml variant used by epubs and by browser engines.

Not sure what problems you are seeing under Sigil.

03-04-2025, 10:25 AM	#1
wanderson Enthusiast Posts: 28 Karma: 10 Join Date: Jul 2017 Location: Austin TX USA Device: Kindle Paperwhite Gen 11, Likebook Mars & TCL NxtPaper 11	MathML namespace declaration in .css not "sticking" I'm editing a equation-heavy epub and I'm using a lot of MathML markups. I'd like for the text to be as economical as possible, so I'd like to avoid this kind of tag: Code: <math xmlns="http://www.w3.org/1998/Math/MathML"> ... </math> and instead use a single namespace declaration in the stylesheet.css, namely: Code: @namespace math url(http://www.w3.org/1998/Math/MathML); which would (theoretically) enable a simpler MathML tag: Code: <math> ... </math> This doesn't seem to be working for me in the Calibre editor / previewer. It may be the case that the namespace is conveyed to the first instance of a <math> tag in a file, but the remaining tags "forget" the namespace designation. What am I doing wrong? Thanks in advance for any help.

03-07-2025, 06:12 PM	#7
KevinH Sigil Developer Posts: 8,759 Karma: 5706256 Join Date: Nov 2009 Device: many	That Sigil ignores that namespace makes no sense. Adding the mathml namespace prefix "math" to the html tag and then using that prefix "math" for each math tag in the file (ie. each tag becomes math:math) should work. That is what namespace prefixes are for. More importantly though math tags do NOT need a prefix at all under the html5 xhtml variant used for epub3 according to the spec. The math tag and its contents is autorecognized as a foreign tag (just like the svg tag) and modern parsers should understand it just fine without the need for declaring any namespace prefix for it. Have you tried without any specific namespace prefix defined for mathml at all? I wonder if this is a limitation of Qt6's webengine's new built in mathml support in some way? Update: It is not. To test with Sigil I opened an epub full of mathml and did a global find and replace to remove all of the math tag namespace declarations that said no prefix needed: ie: xmlns="http://www.w3.org/1998/Math/MathML" and made sure no mathml prefix namespace was defined on the html tag. And sure enough no parsing errors or problems at all. All equations looked as expected. So no math namespace prefix need be defined and no xmlns="http://www.w3.org/1998/Math/MathML" need be added to math tags as it is properly namespaced by the parser under the html5 xhtml variant used by epubs and by browser engines. Not sure what problems you are seeing under Sigil. Last edited by KevinH; 03-07-2025 at 06:31 PM.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Calibre 6.11: "Remove CSS Rules" and "Check Book" Conflicts	enuddleyarbl	Editor	10	01-08-2023 08:33 AM
In DTD declaration, language other than "EN" will generate warning message.	guidaq	Sigil	3	04-07-2016 10:48 PM
Touch "sticking" page turn button	GreenMonkey	Barnes & Noble NOOK	2	10-15-2011 06:23 PM
attribute "scheme" from namespace error in epubcheck 1.0.5	thunderune	ePub	15	06-30-2011 10:57 AM
Namespace declaration	ChrisI	Sigil	1	08-22-2010 06:02 AM

03-04-2025, 12:17 PM	#2
kovidgoyal creator of calibre Posts: 45,342 Karma: 27182818 Join Date: Oct 2006 Location: Mumbai, India Device: Various	namespace declarations in CSS do not change the namespace of tags in html. They just allow css tag based selectors to use namespaces.

03-07-2025, 03:57 PM	#6
DNSB Bibliophagist Posts: 46,149 Karma: 168983734 Join Date: Jul 2010 Location: Vancouver Device: Kobo Sage, Libra Colour, Lenovo M8 FHD, Paperwhite 4, Tolino epos	Sounds like a job for a clip.

Advert

Advert