Method for live symbolic calculations in a mathematical document editor

A mathematical document editor that can perform live symbolic calculations. The mathematical document editor is capable of placing mathematical expressions at any position on a computer screen, that represents a printed document. A symbolic dependency graph is maintained such that it always reflects the mathematical dependencies on the computer screen. Any expression which includes a symbolic evaluation operator is evaluated by a symbolic algebra engine, taking into account all the definitions and constraints upon which the expression depends. If an expression is modified, introduced or deleted, the symbolic dependency graph is used to determine which expression containing the symbolic evaluation operator need to be modified. The present invention ensures that the document is 'up to date' in the sense that all expressions, including those requiring symbolic calculations, are consistent with all antecedent expressions upon which they depend.