# [NTG-context] Numbering subformulas

Procházka Lukáš Ing. - Pontex s. r. o. LPr at pontex.cz
Mon Aug 3 17:47:46 CEST 2015

Hello,

some more observation:

It seems (sub)numbering (sub)formulas can be achieved enclosing expressions into \start/\stop-align.

I wrote a code based on a test suite file:

...\test\doc\context\tests\mkiv\math\formulas-001.tex

----
\starttext
\startsubformulas[eq:sub1]
\placeformula
\startformula
\startalign
\NC a_1 x + b_1 y \NC = c_1 \NR[eq:11]
\NC a_2 x + b_2 y \NC = c_2 \NR[eq:12]
\stopalign
\stopformula
\stopsubformulas

\in{eq:11}[eq:11]
\in{eq:12}[eq:12]

\placeformula
\startformula
\startsubformulas[eq:sub2]
\startalign
\NC a_1 x + b_1 y \NC = c_1 \NR[eq:21]
\NC a_2 x + b_2 y \NC = c_2 \NR[eq:22]
\stopalign
\stopsubformulas
\stopformula

\input knuth

\placeformula
\startformula
\startsubformulas[eq:sub2]
\startalign
\NC a_1 x + b_1 y \NC = c_1 \NR[eq:31]
\NC a_2 x + b_2 y \NC = c_2 \NR[eq:32]
\stopalign
\stopsubformulas
\stopformula

\in{eq:31}[eq:31]
\in{eq:32}[eq:32]
\stoptext
----

Problems are:

1. I am not able to make numbering of eq:31 and eq:32 continue on eq:22, so to have equations numbered:

1a, 1b; 2a, 2b; 2c, 2d

1a, 1b; 2a, 2b; 3a, 3b

(Some text - here: knuth - between 2b and 3a/2c is required.)

(I played with commenting some combinations of lines but with no success.)

So - is there a way how to continue numbering subformulas (after some inserted text) - something like itemizing has \startitemize[continue]?

2. How to affect the numbering style to be "1a" instead "1.a"?

3. @Hans: The test suite file:

...\test\doc\context\tests\mkiv\math\subformulas-001.tex

compiles, but gives "no-reference" "??".

(
The example on wiki:

http://wiki.contextgarden.net/Math/Display#Automatic_Sub-Formula_Numbering

seems to be very ancient as it GIVES the desired result.
)

Lukas

On Mon, 03 Aug 2015 12:20:44 +0200, Procházka Lukáš Ing. - Pontex s. r. o. <LPr at pontex.cz> wrote:

> Hello,
>
> it seems this is a frequent thesis - in the mailing archive, stackoverflow...
>
> Anyway, I'm not able to find a valid way (MWE) how to number subformulas (with option to create a reference name, like 'eq:1a' and 'eq:1b', and to be able to refer to them, like "\ineq[eq:1a] and \ineq[eq:1b]"), so to get something like:
>
> "
> Some text
> 	a + b = c 	(1a)
> and later
> 	d + e = f 	(1b)
> so nothing surprising in [1a] and [1b].
> "
>
> Moreover, on http://wiki.contextgarden.net/Math there is a red "Warning!":
>
> "
> If you consider using ConTeXt for a paper with a proper formula numbering please wait until it is implemented in mkiv. At the moment only a very limited formula numbering is possilbe:
>   number formula(s) with a plain number
>   number formula(s) with a subnumber
>
> Not possible is at the moment:
>   Table of formulas
>   Named subformulas
>   Mixure of formulas and subformulas in one block
>   Reference on a (sub-)formula without having it listed in the Table of formulas
>
> For more details and actual state see mailing list and Summary of formula numbering problem.
> "
>
> I don't know which date this warning comes from, if it is outdated or still valid...
>
> So, finally, what is the PROPER way (if it really exists) in ConTeXt how to typeset subformulas?
>
> (I'm typesetting a large article on physics which contains many math (sub-)formulas, so knowledge of a working tool for Ctx would be nice...)
>
> Best regards,
>
> Lukas
>
>

--
Ing. Lukáš Procházka | mailto:LPr at pontex.cz
Pontex s. r. o.      | mailto:pontex at pontex.cz | http://www.pontex.cz
Bezová 1658
147 14 Praha 4

Tel: +420 241 096 751
Fax: +420 244 461 038
-------------- next part --------------
A non-text attachment was scrubbed...
Name: subformulas-001.log
Type: application/octet-stream
Size: 6120 bytes
Desc: not available
URL: <http://www.ntg.nl/pipermail/ntg-context/attachments/20150803/4b160119/attachment-0002.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: subformulas-001.pdf
Type: application/pdf
Size: 11865 bytes
Desc: not available
URL: <http://www.ntg.nl/pipermail/ntg-context/attachments/20150803/4b160119/attachment-0001.pdf>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: SubForm2.mkiv
Type: application/octet-stream
Size: 4954 bytes
Desc: not available
URL: <http://www.ntg.nl/pipermail/ntg-context/attachments/20150803/4b160119/attachment-0003.obj>