H Glossary (NonNormative)
Overview: Mathematical Markup Language (MathML) Version 2.0
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H Glossary (Nonnormative)
Several of the following definitions of terms have been borrowed or
modified from similar definitions in documents originating from W3C or
standards organizations. See the individual definitions for more
information.

Argument
 A child of a presentation layout schema. That is, `A is an
argument of B' means `A is a child of B and B is a
presentation layout schema'. Thus, token elements have no arguments,
even if they have children (which can only be
malignmark
).

Attribute
 A parameter used to specify some property of an SGML or XML element
type. It is defined in terms of an attribute name, attribute type, and a
default value. A value may be specified for it on a starttag for that
element type.

Axis
 The axis is an imaginary alignment line upon which a fraction line
is centered. Often, operators as well as characters that can stretch, such
as parentheses, brackets, braces, summation signs etc., are centered on
the axis, and are symmetric with respect to it.

Baseline
 The baseline is an imaginary alignment line upon which a glyph
without a descender rests. The baseline is an intrinsic property of the
glyph (namely a horizontal line). Often baselines are aligned (joined)
during typesetting.

Black box
 The bounding box of the actual size taken up by the viewable
portion (ink) of a glyph or expression.

Bounding box
 The rectangular box of smallest size, taking into account the
constraints on boxes allowed in a particular context, which contains some
specific part of a rendered display.

Box
 A rectangular plane area considered to contain a character or
further subboxes, used in discussions of rendering for display. It is
usually considered to have a baseline, height, depth and width.

Cascading Style Sheets (CSS)
 A mechanism that allows authors and readers to attach style
(e.g. fonts, colors and spacing) to HTML and XML documents.

Character
 A member of a set of identifiers used for the organization, control
or representation of text. ISO/IEC Standard 106461:1993 uses the word
`data' here instead of `text'.

Character data (
CDATA
)
 A data type in SGML and XML for raw data that does not include
markup or entity references. Attributes of type
CDATA
may contain
entity references. These are expanded by an XML processor before the
attribute value is processed as CDATA
.

Character or expression depth
 Distance between the baseline and bottom edge of the character
glyph or expression. Also known as the descent.

Character or expression height
 Distance between the baseline and top edge of the character glyph
or expression. Also known as the ascent.

Character or expression width
 Horizontal distance taken by the character glyph as indicated in
the font metrics, or the total width of an expression.

Condition
 A MathML content element used to place a mathematical condition on
one or more variables.

Contained (element A is contained in element B)
 A is part of B's content.

Container (Constructor)
 A nonempty MathML Content element that is used to construct a
mathematical object such as a number, set, or list.

Content elements
 MathML elements that explicitly specify the mathematical meaning
of a portion of a MathML expression (defined in Chapter 4 [Content Markup]).

Content token element
 Content element having only
PCDATA
, sep
and presentation expressions as content. Represents either an identifier
(ci
) or a number (cn
).

Context (of a given MathML expression)
 Information provided during the rendering of some MathML data to
the rendering process for the given MathML expression; especially
information about the MathML markup surrounding the expression.

Declaration
 An instance of the declare element.

Depth
 (of a box) The distance from the baseline of the box to the bottom
edge of the box.

Direct subexpression
(of a MathML expression `E')
 A subexpression directly contained in E.

Directly contained
(element A in element B)
 A is a child of B (as defined in XML), in other words
A is contained in B, but not in any element that is itself contained in
B.

Document Object Model
 A model in which the document or Web page is treated as an object
repository. This model is developed by the DOM Working Group (DOM) of the
W3C.

Document Style Semantics and Specification Language (DSSSL)
 A method of specifying the formatting and transformation of
SGML documents. ISO International Standard 10179:1996.

Document Type Definition (DTD)
 In SGML or XML, a DTD is a formal definition of the elements and
the relationship among the data elements (the structure) for a particular
type of document.

Em
 A fontrelative measure encoded by the font. Before electronic
typesetting, an
em
was the width of an
`M' in the font. In modern usage, an em
is either specified by the designer of the font or is taken to be the
height (point size) of the font. Em's are typically used for fontrelative
horizontal sizes.

Ex
 A fontrelative measure that is the height of an `x'
in the font.
ex
s are typically used for
fontrelative vertical sizes.

Height
 (of a box) The distance from the baseline of the box to the top
edge of the box.

Inferred
mrow
 An
mrow
element that is
`inferred' around the contents of certain layout schemata when
they have other than exactly one argument. Defined precisely in Section 3.1.6 [Summary of Presentation Elements]

Embedded object
 Embedded objects such as Java applets, Microsoft Component Object
Model (COM) objects (e.g. ActiveX Controls and ActiveX Document
embeddings), and plugins that reside in an HTML document.

Embellished operator
 An operator, including any `embellishment' it may
have, such as superscripts or style information. The
`embellishment' is represented by a layout schema that
contains the operator itself.
Defined precisely in Section 3.2.5 [Operator, Fence, Separator or Accent
(
mo
)].

Entity reference
 A sequence of ASCII characters of the form
&name;
representing some other data, typically a
nonASCII character, a sequence of characters, or an external source of
data, e.g. a file containing a set of standard entity definitions such as
ISO Latin 1.

Extensible Markup Language (XML)
 A simple dialect of SGML intended to enable generic SGML to be
served, received, and processed on the Web.

Fences
 In typesetting, bracketing tokens like parentheses, braces, and
brackets, which usually appear in matched pairs.

Font
 A particular collection of glyphs of a typeface of a given size,
weight and style, for example `Times Roman Bold 12 point'.

Glyph
 The actual shape (bit pattern, outline) of a character.
ISO/IEC Standard 95411:1991 defines a glyph as a recognizable abstract
graphic symbol that is independent of any specific design.

Indirectly contained
 A is contained in B, but not directly contained in B.

Instance of MathML
 A single instance of the top level element of MathML, and/or a
single instance of embedded MathML in some other data format.

Inverse function
 A mathematical function that, when composed with the original
function acts like an identity function.

Lambda expression
 A mathematical expression used to define a function in terms of
variables and an expression in those variables.

Layout schema (plural: schemata)
 A presentation element defined in chapter 3, other than the token
elements and empty elements defined there (i.e. not the elements defined in
Section 3.2 [Token Elements] and Section 3.5.5 [Alignment Markers], or the
empty elements
none
and
mprescripts
defined in Section 3.4.7 [Prescripts and Tensor Indices
(mmultiscripts
)]).
The layout schemata are never empty elements (though their content may
contain nothing in some cases), are always expressions, and all allow any
MathML expressions as arguments (except for requirements on argument count,
and the requirement for a certain empty element in mmultiscripts
).

Mathematical Markup Language (MathML)
 The markup language specified in this document for describing
the structure of mathematical expressions, together with a mathematical
context.

MathML element
 An XML element that forms part of the logical structure of a
MathML document.

MathML expression (within some valid MathML
data)
 A single instance of a presentation element, except for the empty
elements
none
or
mprescripts
, or an instance of malignmark
within a token element (defined below);
or a single instance of certain of the content elements
(see Chapter 4 [Content Markup] for a precise definition of which ones).

Multipurpose Internet Mail Extensions (MIME)
 A set of specifications that offers a way to interchange text in
languages with different character sets, and multimedia content among many
different computer systems that use Internet mail standards.

Operator, content element
 A mathematical object that is applied to arguments using the
apply
element.

Operator, an
mo
element
 Used to represent ordinary operators, fences, separators in MathML
presentation. (The token element
mo
is defined in
Section 3.2.5 [Operator, Fence, Separator or Accent
(mo
)]).

OpenMath
 A general representation language for communicating mathematical
objects between application programs.

Parsed character data (
PCDATA
)
 An SGML/XML data type for raw data occurring in a context where
text is parsed and markup (for instance entity references and element
start/end tags) is recognized.

Point
 Point is often abbreviated `pt'. The value of 1 pt
is approximately 1/72 inch. Points are typically used to specify
absolute sizes for fontrelated objects.

Predefined function
 One of the empty elements defined in Section 4.2.3 [Functions, Operators and Qualifiers] and used with the
apply
construct to build function applications.

Presentation elements
 MathML tags and entities intended to express the syntactic
structure of mathematical notation (defined in Chapter 3 [Presentation Markup]).

Presentation layout schema
 A presentation element that can have other MathML elements as
content.

Presentation token element
 A presentation element that can contain only parsed character data
or the
malignmark
element.

Qualifier
 A MathML content element that is used to specify the value of a
specific named parameter in the application of selected predefined
functions.

Relation
 A MathML content element used to construct expressions such as
a < b.

Render
 Faithfully translate into applicationspecific form allowing native
application operations to be performed.

Schema
 Schema (plural: schemata or schemas). See `presentation layout
schema'.

Scope of a declaration
 The portion of a MathML document in which a particular
definition is active.

Selected subexpression
(of an
maction
element)
 The argument of an
maction
element (a
layout schema defined in Section 3.6 [Enlivening Expressions]) that is (at any
given time) `selected' within the viewing state of a MathML
renderer, or by the selection
attribute when the
element exists only in MathML data. Defined precisely in the abovementioned
section.

Spacelike (MathML expression)
 A MathML expression that is ignored by the suggested rendering
rules for MathML presentation elements when they determine operator forms
and effective operator rendering attributes based on operator positions in
mrow
elements. Defined precisely in Section 3.2.7 [Space (mspace
)].

Standard Generalized Markup Language (SGML)
 An ISO standard (ISO 8879:1986) that provides a formal
mechanism for the definition of document structure via DTDs (Document
Type Definitions), and a notation for the markup of document instances
conforming to a DTD.

Subexpression (of a MathML expression
`E')
 A MathML expression contained (directly or indirectly) in the
content of E.

Suggested rendering rules for
MathML presentation elements
 Defined throughout Chapter 3 [Presentation Markup]; the ones that use other
terms defined here occur mainly in Section 3.2.5 [Operator, Fence, Separator or Accent
(
mo
)] and in
Section 3.6 [Enlivening Expressions].

T_{E}X
 A software system developed by Professor Donald Knuth for
typesetting documents.

Token element
 Presentation token element or a Content token element. (See
above.)

Toplevel element (of MathML)

math
(defined in Chapter 7 [The MathML Interface]).

Typeface
 A typeface is a specific design of a set of letters, numbers and
symbols, such as `Times Roman' or `Chicago'.

Valid MathML data
 MathML data that (1) conforms to the MathML DTD, (2) obeys the
additional rules defined in the MathML standard for the legal contents and
attribute values of each MathML element, and (3) satisfies the EBNF grammar
for content elements.

Width (of a box)
 The distance from the left edge of the box to the right edge of the
box.

Extensible Style Language (XSL)
 A style language for XML developed by W3C. See XSL FO and XSLT.

XSL Formatting Objects (XSL FO)
 An XML vocabulary to express formatting, which is a part of XSL.

XSL Transformation (XSLT)
 A language to express the transformation of XML documents
into other XML documents.
Overview: Mathematical Markup Language (MathML) Version 2.0
Previous: G Sample CSS Style Sheet for MathML (Nonnormative)
Next: I Working Group Membership and Acknowledgments (Nonnormative)