Re: Nabla operator appears italic in formula

[Hans Hagen <pragma@wxs.nl>]

On 3/24/2013 12:23 PM, Otared Kavian wrote:
>
> On 24 mars 2013, at 11:24, Hans Hagen <pragma@wxs.nl> wrote:
>
>> On 3/23/2013 9:34 PM, Xenia wrote:
>>> Dear context list,
>>>
>>> using the nabla symbol ∇ in formulas, I wondered why it looks italic and
>>> not upright as for example in [1].
>>> I attach an example.
>>
>> Because that's how it's defined in math italics ... is nabla always supposed to be upright in standard math italic mode?
>>
>> (I'll change the \nable definition to \unexpanded\def\nabla{∇}.)
>>
>> Hans
>
> Hi,
>
> \nabla should be italic if all other math greek symbols, like \Omega, \Gamma, \sum, ect are set in italic. Otherwise \nabla and all such symbols should be upright.
> Would it be possible to make this optional in math italics, something like
> 	\setupmathematics[mathsymbols=italic]
> or
> 	\setupmathematics[mathsymbols=upright]
> Maybe this should be set when one chooses the greek letters to be italic or upright in mathematics.

That is already there

\setupmathematics
   [lcgreek=italic,
    ucgreek=normal]

(normal, italic, none)

I've added sygreek so that one can also influence the nable and 
differential (default normal). I tested with:

\starttext
     \startTEXpage
         \startlines
             \type{--}: \mathematics{    \nabla \phi = ∇ ϕ = 0}
             \type{it}: \mathematics{\it \nabla \phi = ∇ ϕ = 0}
             \type{bf}: \mathematics{\bf \nabla \phi = ∇ ϕ = 0}
             \type{bi}: \mathematics{\bi \nabla \phi = ∇ ϕ = 0}
             \type{tf}: \mathematics{\tf \nabla \phi = ∇ ϕ = 0}
             \blank
             \type{--}: \mathematics{    \mathgreekupright \nabla \phi = 
∇ ϕ = 0}
             \type{it}: \mathematics{\it \mathgreekupright \nabla \phi = 
∇ ϕ = 0}
             \type{bf}: \mathematics{\bf \mathgreekupright \nabla \phi = 
∇ ϕ = 0}
             \type{bi}: \mathematics{\bi \mathgreekupright \nabla \phi = 
∇ ϕ = 0}
             \type{tf}: \mathematics{\tf \mathgreekupright \nabla \phi = 
∇ ϕ = 0}
             \blank
             \setupmathematics[sygreek=italic]
             \type{--}: \mathematics{    \nabla \phi = ∇ ϕ = 0}
             \type{it}: \mathematics{\it \nabla \phi = ∇ ϕ = 0}
             \type{bf}: \mathematics{\bf \nabla \phi = ∇ ϕ = 0}
             \type{bi}: \mathematics{\bi \nabla \phi = ∇ ϕ = 0}
             \type{tf}: \mathematics{\tf \nabla \phi = ∇ ϕ = 0}
         \stoplines
     \stopTEXpage
\stoptext


Hans


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