Math object encapsulates quasi-prefix form

To represent the quasi-prefix form, we extend the attributed tree model defined in the previous section with object math object. We define six such attributes in fig:math-object.

 [thesisfigure420]

: A math object with attributes. Each of the attributes themselves contain math objects.

A math object may have any or all of these attributes. An attribute can have a math object as content.

Here are the basic object types in this representation:

• Math object: Basic representation for mathematical content. It is a subtype of document.
  • Attributes: A list of math attribute objects.
  • Content: String representing the content.
  • Children: List of children. Each child is a math object.
• Math attribute: Captures visual annotations. Superscript, subscript, etc. have the same structure and are subclasses of class math attribute.
  • Name: Attribute name, e.g., superscript, accent.
  • Content: Contents of this attribute as a math object.

• Content: ``x''.
• Children: None.
• Attributes: A list of attribute objects:
  • Superscript: Subtype of math attribute.
    • Name: Superscript.
    • Content: ``k''.
  • Subscript: subtype of object math attribute.
    • Name: Subscript.
    • Content: ``1''.

The representation can capture mathematical expressions with arbitrarily complex visual attributes. Let [tex2html_wrap5294] denote the math object shown above. Then

[displaymath5278]

would be represented by math object [tex2html_wrap5296] shown below:

• Content: ``x''.
• Superscript: [tex2html_wrap5298].
• Subscript: [tex2html_wrap5300].