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Re: [STDS-802-11-TGM] Italics in equations



--- This message came from the IEEE 802.11 Task Group M Technical Reflector ---

I see this is scheduled to be discussed on today's teleconf, so…

 

Please be aware of the guidance in the IEEE Style Guide:

 

15.3 Presentation of equations

Certain types of material in displayed equations are automatically italic. Some simple general rules apply.

All variables are italic. (e.g., x, y, n). Function names and abbreviations are Roman (sin, cos, sinc, sinh), as

are units or unit abbreviations (e.g., deg, Hz,) complete words (e.g., in, out), and abbreviations of words

(e.g., max, min), or acronyms (e.g., SNR). Single letter superscripts and subscripts may be italic even if

they are abbreviations, unless this leads to inconsistency between italic and roman characters for similar

types of subscripts.

 

The problem is that these so-called simple general rules are not

simple, because they intersect.  The specific issue is things which

are both a "word" (so should be roman) and a "variable" (so should

be italic).  So if you have

 

   Time = Distance / Speed

 

then are the sets of letters "words" or "variables"?

 

I (currently) take no particular position, but I do think it would

be desirable to strive for consistency.

 

BTW, I note some other rules which may be pertinent to comments made

on D4.0, e.g.:

 

A multiplication sign (×), not the letter “x” or a multidot (∙), should be used to indicate multiplication.

 

References:

 

https://www.ieee.org/documents/style_manual.pdf

https://development.standards.ieee.org/myproject/Public/mytools/draft/styleman.pdf

 

(I am not sure how these two relate; they seem in places to be mutually

inconsistent.)

 

Mark

 

--

Mark RISON, Standards Architect, WLAN   English/Esperanto/Français

Samsung Cambridge Solution Centre       Tel: +44 1223  434600

Innovation Park, Cambridge CB4 0DS      Fax: +44 1223  434601

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From: ***** IEEE stds-802-11-tgm List ***** [mailto:STDS-802-11-TGM@xxxxxxxx] On Behalf Of Stephens, Adrian P
Sent: 22 June 2015 15:36
To: STDS-802-11-TGM@xxxxxxxxxxxxxxxxx
Subject: [STDS-802-11-TGM] Italics in equations

 

--- This message came from the IEEE 802.11 Task Group M Technical Reflector ---

Hello Edward and Emily,

 

Please be aware of the guidance in the IEEE Style Guide:

 

15.3 Presentation of equations

Certain types of material in displayed equations are automatically italic. Some simple general rules apply.

All variables are italic. (e.g., x, y, n). Function names and abbreviations are Roman (sin, cos, sinc, sinh), as

are units or unit abbreviations (e.g., deg, Hz,) complete words (e.g., in, out), and abbreviations of words

(e.g., max, min), or acronyms (e.g., SNR). Single letter superscripts and subscripts may be italic even if

they are abbreviations, unless this leads to inconsistency between italic and roman characters for similar

types of subscripts.

 

We have numerous comments this time round (mainly from Guido) asking for changes.

 

For example comment 6853: “Compare the formating of "Duration = (i - 1) x (TXTIME(CF-End) + SIFS)" with G(x) in 8.2.4.8. In G(x) all variables are written in italics. In the present formula only i is written in italics. However, Duration is variable too and thus should be written in italics too.”

 

The cited G(x) is at 590.53.   Compared to the style guide,  590.53 is almost correct, except the “G” should be Roman, as it represents a function.

The cited problematical equation is “Duration = (i– 1) × (TXTIME(CF-End) + SIFS)”,  all except the “i” is Roman.

 

According to the rules TXTIME() is a function, and should be Roman.

CF-End is not a variable,  but a word,  although what a word is doing as a parameter is anybody’s guess.

Likewise SIFS.    It would have meant more sense if it was aSIFSTime,  because that is an attribute with

a value. Even that should be Roman because it is a “word”. Finally “Duration” is a whole word,  and so should be Roman.

 

So,  all of the proposed changes are,   IMHO,  needless work,  and move us further away from the IEEE’s Style guide.

 

I would urge caution when resolving such comments.  If we do want to spend effort making equations clearer, 

then we should look to replace “words and self-defining phrases” in equations with 1-character subscripted variables.

 

 

For example:

                t = (time to drink a beer) * 2 + time to get another order in

 

is probably better represented: (_ = subscript)

 

                t = (2 x t_drink) + t_order

where

                t_drink is the time taken to drink a beer

                t_order is the time to order a beer

 

 

Purists will realize that my equation,  while pedagogically useful is semantically and economically flawed.

 

Best Regards,

 

Adrian P STEPHENS

 

Tel: +44 (1793) 404825 (office)
Tel: +1 (971) 330 6025 (mobile)

 

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