RE: [EXTERNAL] Re: Unicode 14

Variation selector sequences aren’t currently defined for the various sizes of delimiters. The groupings generally can be figured out by how deeply the delimiters are nested. LaTeX and OfficeMath can increase the delimiter sizes automatically, so that \big, etc., aren’t needed except to overrule the sizing algorithm. I don’t think the UTC would accept a proposal to use variation selectors for this purpose since the semantics can generally be figured out without knowing the display sizes. Admittedly there are cases where an algorithm can’t figure out the nesting unless the plain text includes appropriate \open and \close attributes (see UnicodeMath<> Sec. 3.1).


From: Ross Moore <>
Sent: Saturday, June 26, 2021 4:03 PM
To: Murray Sargent <>
Cc: Will Robertson <>; David Carlisle <>;
Subject: Re: [EXTERNAL] Re: Unicode 14

Hi all,

It's great to hear that variation selectors are being used with more math symbols.

Has there ever been, or is there already existing, a proposal to use variation
selectors for different sizes of brackets and parentheses?
as obtained with TeX’s  \big  \Big  \bigg  \Bigg  delimiter specifiers?

These are commonly used to clarify the groupings within complicated expressions.
Finding published examples would not be hard; especially in educational materials.

Just asking.



On 26 Jun 2021, at 2:39 pm, Murray Sargent <<>> wrote:

We only targeted math-script styles of A-Z in this effort (see 20275r-math-calligraphic.pdf (<>). That was tricky in its own right due to differing current usage of the math-script characters. Adding sans-serif normal weight Greek letters has different considerations and can be a separate proposal.


From: Will Robertson <<>>
Sent: Friday, June 25, 2021 5:09 PM
To: David Carlisle <<>>
Subject: [EXTERNAL] Re: Unicode 14

Hi David

Thanks for circulating this. Great news. I take it there has been no addition of sans serif normal weight Greek to fill out the variants available there?

(There is bold sans serif Greek but not normal weight, which makes user interfaces for these symbols awkward.)

It’s been on my todo list to revive discussions on this for years but life has got in the way…

(From phone)

On 26 Jun 2021, at 05:52, David Carlisle <<>> wrote:

The release of Unicode 14 is delayed this year due to pressures due to
Covid, however it is expected in September.

It contains the largest change to the Math Character blocks since the
math alphabets were added at Unicode 3.1.

Unicode now recognises the two script styles Roundhand and Chancery
(\mathscr and \mathcal in most LaTeX math font packages).

They share the same code points as the existing "ambiguous" script math
alphabet block but (for upper case) you may use the variant selectors
U+FE00 and U+FE01 to specify Chancery or Roundhand respectively.

See the beta version of the Unicode code charts at<>

I have made an editor's draft of the HTML/XML Entities draft updated to
Unicode 14, and referencing these new characters.<>

As Unicode 14 is in beta this is just in a u14 branch in the git
repository but I have set github pages to display from that branch for now.

There are no changes to the normative entity definitions so & A s c r ;
will still select the code point U+1D49C and not use the variant
selector suffixes to force either style.

It may be a while before font support exists for these possibilities but
many math fonts (eg Stix Two Math) already have both sets of glyphs, but
currently the access is via font-specific font feature selection.

There have been some other additions to Unicode since the last release
of the entities spec, notably U+FE00 may now also be used to distinguish
0 from slashed zero and the two forms of the empty set (added at Unicode
9 I think). Again the entities are not changing so (unfortunately) empty
and varnothing both refer to U+2205 even though U+2205+FE00 is "EMPTY
SET zero with long diagonal stroke"

This is a first draft update not reviewed by anybody, so comments
welcome. At some point it may form the basis of an update to<> but no immediate plans for that,
next year perhaps.


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Received on Sunday, 27 June 2021 00:19:05 UTC