System and method for convergent document collaboration

A method for maintaining a document outline on a user interface, the method comprising:

• displaying the document outline on the user interface, the document outline comprising a plurality of levels, each of the plurality of levels representing a different section of a document;
• maintaining, in a non-transitory computer-readable medium, a causal graph data structure representing the document outline, wherein the causal graph data structure includes a plurality of structure nodes, each structure node representing a different level of the plurality of levels;
• receiving, via the user interface, a formatting of a level of the plurality of levels;
• in response to the formatting, inserting an attribute node as a child of the structure node representing the level for which the formatting was received, wherein the attribute node indicates the type of formatting that is to be applied;
• applying the indicated type of formatting to a section of the document within the level for which the formatting was received;
• and
• updating the user interface to display the section as being formatted according to the indicated type.

A method for maintaining a document on a user interface, the method comprising:

• displaying the document outline on the user interface, wherein the document includes a plurality items at a plurality of Z-depth levels;
• maintaining, in a non-transitory computer-readable medium, a causal graph data structure that includes a plurality of structure nodes, each structure node representing a level of the plurality of Z-depth levels;
• receiving, via the user interface, a gesture indicating a move of an item from a first Z-depth level to a second Z-depth level;
• in response to the gesture
• inserting a transition node into the causal graph data structure, wherein the transition node has a parent node representing the second Z-depth level, and
• updating a structure node representing the Z-depth level being moved so that its parent node is the transition node;
• and
• updating the user interface to display the item within the document as having been moved.