D Glossary (Non-Normative)
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
- 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
- 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 start-tag for that
- 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.
- 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)
- 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.
- A rectangular plane area considered to contain a character or
further sub-boxes, used in discussions of rendering for display. It is
usually considered to have a baseline, height, depth and width.
- Cascading Style Sheets (CSS)
- A language that allows authors and readers to attach style
(e.g. fonts, colors and spacing) to HTML and XML documents.
- A member of a set of identifiers used for the organization, control
or representation of text. ISO/IEC Standard 10646-1:1993 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.
- 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 non-empty Content MathML 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,
and presentation expressions as content. Represents either an identifier
ci) or a number (
- 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.
- An instance of the declare element.
- (of a box) The distance from the baseline of the box to the bottom
edge of the box.
- Direct sub-expression
(of a MathML expression "E")
- A sub-expression 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
- 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
- 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.
- A font-relative 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 font-relative
- A font-relative measure that is the height of an "x"
in the font. "ex"s are typically used for
font-relative vertical sizes.
- (of a box) The distance from the baseline of the box to the top
edge of the box.
mrow element that is
"inferred" around the contents of certain layout schemata when
they have other than exactly one argument. Defined precisely in Section 3.1.9 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 plug-ins 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
- Entity reference
- A sequence of ASCII characters of the form
&name; representing some other data, typically a
non-ASCII 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.
- In typesetting, bracketing tokens like parentheses, braces, and
brackets, which usually appear in matched pairs.
- A particular collection of glyphs of a typeface of a given size,
weight and style, for example "Times Roman Bold 12 point".
- The actual shape (bit pattern, outline) of a character.
ISO/IEC Standard 9541-1:1991 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
<malignmark/>, or the
mprescripts defined in Section 3.4.7 Prescripts and Tensor Indices
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
- Mathematical Markup Language (MathML)
- The markup language specified in this document for describing
the structure of mathematical expressions, together with a mathematical
- MathML element
- An XML element that forms part of the logical structure of a
- MathML expression (within some valid MathML
- A single instance of a presentation element, except for the empty
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).
- Multi-purpose 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
- Operator, an
- 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
- 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 is often abbreviated "pt". The value of 1 pt
is approximately 1/72 inch. Points are typically used to specify
absolute sizes for font-related objects.
- 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
- Presentation token element
- A presentation element that can contain only parsed character data
- A MathML content element that is used to specify the value of a
specific named parameter in the application of selected pre-defined
- A MathML content element used to construct expressions such as
a < b.
- Faithfully translate into application-specific form allowing native
application operations to be performed.
- Schema (plural: schemata or schemata). See "presentation layout
- Scope of a declaration
- The portion of a MathML document in which a particular
definition is active.
- Selected sub-expression
- The argument of an
maction element (a
layout schema defined in Section 3.7 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 aforementioned
- Space-like (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
- 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.
- Sub-expression (of a MathML expression
- 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 3.7 Enlivening Expressions.
- A software system developed by Professor Donald Knuth for
- Token element
- Presentation token element or a Content token element. (See
- Top-level element (of MathML)
math (defined in Section 2.2 The Top-Level
- 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
- 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.