Glossary

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 start-tag for that element type.

Axis
The axis is an imaginary alignment line upon which a fraction line is centered. Often, characters that can stretch such as parenthesis, brackets, braces, summation signs, etc., and operators 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 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 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.

Character Data (CDATA)
A SGML/XML data type for raw data which 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 know 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 non-empty MathML Content element that is used to construct a mathematical object such as a number, set, or list.

Content elements
MathML elements which explicitly specify the mathematical meaning of a portion of a MathML expression (defined in Chapter 4 of the MathML standard).

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 which surrounds that 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 which is directly contained in E.

Directly contained (element A in element B)
A is a child of B (as defined in XML); i.e. A is contained in B, but not in any element which 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 (Member Only) ) of the W3C.

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

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

Em
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 horizontal sizes.

Ex
A font-relative measure that is the height of an 'x' in the font. 'ex's are typically used for font-relative 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 which is "inferred" around the contents of certain layout schemata when they have other than exactly one argument. Defined precisely in Section 3.1.5.

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 which 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 which contains the operator itself. Defined precisely in Section 3.2.4.

Entity reference
A sequence of ASCII characters of the form &name; which represents some other data, typically a non-ASCII character, a sequence of characters, or an external source of data, eg. a file containing a set of standard entity definitions such as ISOLat1.

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, eg "Times Roman Bold 12 point".

Glyph
The actual shape (bit pattern, outline) of a character image.

Input syntax layer
A planned MathML extension mechanism designed to facilitate hand entry of MathML content.

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

Instance of MathML
A single instance of the toplevel 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 Sections 3.3 - 3.6, other than the empty elements defined there (i.e. not the elements defined in 3.5.4 (about alignment) or the empty elements [none/] and [mprescripts/] defined in 3.4.7 (about <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 argument count requirements and the requirement for a certain empty element in <mmultiscripts>).

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

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

MathML expression (within some well-formed 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 Section 4 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 multi-media 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. (<mo>, a token element, is defined in Section 3.2.4.)

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 recognised.

Pt
Point (pt), 1 pt = 1/72 inch. Points are typically used to specify absolute sizes for font-related objects.

Pre-defined function
One of the empty elements defined in section 4.2.3 and used with the apply construct to build function applications.

Presentation elements
MathML tags and entities intended to express the syntactic structure of math notation (defined in Chapter 3 of the MathML standard).

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

Presentation token elements
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 pre-defined functions.

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

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

Scope of a Declaration
The portion of a MathML document to over 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) which 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 Section 3.6.

Spacelike (MathML expression)
A MathML expression which 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 3.2.6.

Standard Generalized Markup Language (SGML)
An ISO standard (ISO 8879:1986) which 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 E's content.

Suggested rendering rules for MathML presentation elements
Defined throughout Chapter 3; the ones which use other terms defined here occur mainly in Section 3.2.4, but also in 3.6 and perhaps elsewhere.

TeX
A software system written by 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)

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

Well-Formed MathML data
MathML data which (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; (3) Satisfies the EBNF grammar for content elements.

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