# 0.5 Presentation token element (mo)  (Page 2/6)

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MathML also allows improvisation of an operator rendered by “mo” element. This generally makes use of other characters rendering elements such as “mi” or "mn" elements in addition to "mo" element and their combination with layout elements like “mfrac” and scripting elements (“msub”, “msup” etc.) Simply put, MathML treats an expression with a “mo” element at core and improvised by other elements - as an operator of class known as “embellished” operator.

Consider encoding for a differentiation operator "&DifferentialD;" . This operator when applied to a variable, say t, is represented as $dt$ In mathematics, however, $\frac{d}{dt}$ is itself considered to be an operator. The whole block consisting of “mfrac” element is, thus, an embellished operator.

<m:mfrac> <m:mo> &DifferentialD; </m:mo> <m:mrow> <m:mo> &DifferentialD; </m:mo> <m:mi> x </m:mi> </m:mrow> </m:mfrac>

## Additional attribute : default values

Default values to the attributes of “mo” element are set in accordance with the values contained in “operator dictionary”, which specifies “form”, “fence”, “stretchy”, “lspace” and “rspace” attributes for different operators. The renderer maintains an operator dictionary for most of the operators. W3C recommends a prototype of operator dictionary. These recommendations can be viewed at www.w3.org/TR/MathML2/appendixf.html . If the dictionary does not provide the value for the attribute, then attribute is set with default value as given here:

## Default values

• form : set by position/context
• fence : false
• separator : false
• lspace : thickmathspace
• rspace : thickmathspace
• stretchy : false
• symmetric : true
• maxsize : infinity
• minsize : 1
• largeop : false
• movablelimits : false
• accent : false

## Attribute value types

• form : prefix | infix | postfix
• lspace : number h-unit | namedspace
• rspace : number h-unit | namedspace

The "form" attribute specifies whether an operator shall be rendered as "prefix" or "postfix" or "infix" operator. These form types determine space around the operator (left and right of it). Each form type is associated with two attributes ("lspace" and "rspace"), which implements its left space ("lspace") and right space ("rspace"). It is important to understand that form types are basically specification about space around operator and about its role with respect to other elements.

The default value of “form” attribute is set in accordance with three rules, involving "mrow" element. The token elements, including "mo" element, is composed within explicit or inferred "mrow" element. The position of an operator within the "mrow" in horizontal sequence determines the form type of the operator. If operator is the first element, then its form is inferred as "prefix"; if it is in the intermediate position, then its form is inferred as "infix”; and if it is in the end position, then its form is inferred as "postfix". Corresponding to each form, operator library specifies "lspace" and "rspace". It is, however, not necessary that each of the operator has all the three form types. The nature of operator determines the type of forms that a particular operator should be associated with. For example, "+" operator has entries for "prefix" and "infix", but not for "postfix" in the operator dictionary, because "postfix" form of "+" operator is not expected to be placed at the end of an expression.

#### Questions & Answers

Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
hi
Loga
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
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Source:  OpenStax, A primer in mathml. OpenStax CNX. Apr 19, 2006 Download for free at http://cnx.org/content/col10345/1.16
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