Glossary

Attribute
A parameter to (property of) an SGML or XML element (specified in the start tag) that is composed of an attribute name and a value.

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 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.

Block level tag
A term used for categorizing display style (math in between paragraphs) MathML elements.

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

Character
A member of a set of identifiers used for the organization, control or representation of text.

Character Data (CDATA)
A SGML data type for raw data which does not include markup or entity references.

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 level tag
A term used for categorizing inline (math as part of a paragraph) MathML elements.

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

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

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

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.

Depth
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 Working Group ( DOM )
A model in which the document or Web page is treated as an object repository. This model is developed by the DOM
working group 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.

Height
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 schema when they have other than exactly one argument. Defined precisely in Section 3.1.5.

Embedded object
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 layout schema which contain 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" (see the comp.fontsFAQ).

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.

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 describes 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 -- 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.

Parser Character Data (PCDATA)
A SGML data type for raw data occurring in a context in which entity references may occur.

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 tokens elements
A presentation element that can have only parsed character data as content.

Rendering

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
One of the presentation elements defined in Section 3.2 [<mi>, etc] or Section 3.5.4 [alignment elements, which are empty], other than an empty element which (in a particular instance) occurs inside a token element. All token elements are either empty, or allow only PCDATA and/or <malignmark/> as content. All token elements are MathML expressions. Not all empty presentation elements are token elements.

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.

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