Hierarchy Diagrams

These diagrams illustrate portions of the hierarchical (nested) structure of this Tag Set. Each diagram has one element “root” and may illustrate the structures of several additional elements. For each element illustrated, its name appears in a box on the left, with lines to boxes for each of its possible child-elements, which are in a column on the right.
Boxes for child elements can have names and/or symbols within. If the box has merely “...”, it means that the actual content has been omitted, to save space or improve clarity. If it has merely an icon of a page with lines, it stands for text content rather than an actual element.
If a box has an element name, then symbols at the left end of the box indicate whether that element is required and/or repeatable. These symbols are called “occurrence indicators”:
item is optional (zero or one)
item may occur any number of times (zero or more)
item must occur at least once, but may occur any number of times (one or more)
vertical bar on the left of the box: item is the “document element”, the top-most element, such as <article> or <book> and is therefore required
(no symbol)
item must occur exactly once
The symbols at the right end of a box have these meanings:
˜ (a tilde)
the item may take one or more attributes
vertical bar on the right of the box: the item is expanded elsewhere (For example, if an element is permitted in multiple places within a certain parent element, there is little point in repeating its information many times.)
The lines that connect a box to boxes on its right may either be squared-off or direct (angled) lines. The squared-off lines mean the items to the right must occur in the order shown; the angled lines indicate that any order is permitted.
For more details and examples see the Document Hierarchy Diagrams section.

Key to the Near & Far Diagrams

Element Occurrences

../graphics/nf-elem-req.gif Required
../graphics/nf-elem-opt.gif Optional. May occur zero or one times.
../graphics/nf-elem-plus.gif Required, repeatable. May occur one or more times.
../graphics/nf-elem-mul.gif Optional, repeatable. May occur zero or more times.

Additional Symbols Associated with Elements

../graphics/nf-elsewhere.gif Element content is expanded elsewhere in the diagram.
../graphics/nf-attributes.gif The element has attributes.
../graphics/nf-collapse.gif One or more elements collapsed for clarity
../graphics/nf-root.gif Element is the root element of the model.
../graphics/nf-pcdata.gif Text, numbers, and special characters

Grouping Elements

../graphics/nf-req-seq.gif Required sequence: Element1 followed by Element2 followed by Element3
../graphics/nf-or-seq.gif Choice of sequence: Element1 or Element2 or Element3

Compound Examples

../graphics/nf-compound1.gif Zero or more repetitions of Element1 or Element2 or Element3 followed by zero or one occurrences of Element4
../graphics/nf-compound2.gif Zero or one occurrences of either Element1 followed by Element2 followed by Element3 or one or more occurrences of Element4
../graphics/nf-compound3.gif Either one or more repetitions of Element1 followed by Element2 or one or more occurrences of Element4
Subsidiary sections:

Top-level element: Article

Processing Metadata

Front Matter

Body and Section

Back Matter

Floating Objects

Sub-article and Response

Body Blocks


All Diagrams in Alphabetical Order