When you work with a collection that includes material belonging to different subjects, you will probably want to keep different subjects in different sections of the knowledge tree (in the contents window). You will probably also often want to design your items differently for questions in literature and differently for questions related to the maths.

To help you keep different subjects separate, SuperMemo introduces the concept of a category. A category is a section of knowledge tree in the contents window. It is used for keeping material related to a single subject. Elements added to a given category may use their own template that determines the appearance of particular components, colors, fonts, sizes of images, number of sound components, etc.

Try creating a new category:

1. select a branch in the knowledge tree in the contents window (e.g. click it)
2. press Ctrl+D (note the change in the category combo box on the main toolbar)
3. press Ctrl+A to add the first child to your new category
4. click Contents at the top of the element window to see how the newly added element has become the first child in the category

A single knowledge category is characterized by the following attributes:

• category name - the name of the category (e.g. Geography)
• default template - template that determines the look of elements within the category
• root node - an element which is the ascendant of all elements included in the category (i.e. all elements in the category are descendants of the root node). By default, the title of the root node element is used as the name of the category (e.g. Geography)
• hook node - a descendant of a root node (or the root node itself) to which new elements are added as children with Add new (or Ctrl+A). Note that Add new adds elements to the hook of the current category (as selected in the category combo box on the main toolbar). Once the number of children in a given hook node exceeds a defined limit, a new hook node is chosen (by the user or automatically by SuperMemo). By definition, the new hook is always a descendant of the root node (or is the same as the root node)

Tools : Categories can be helpful in managing a large number of categories. Individual attributes of a given category can be changed there (name, template, root and hook). Category name can be changed (in Tools : Categories) by typing in a new value. Default template can be changed by typing in the new name or by double clicking the template field and selecting a new template from the template registry. New root or hook nodes can be typed in or selected from among items included in the text registry (including the titles). Note that it is more convenient to determine the root and hook nodes by means of options on the contents pop-up menu: Create new category, Make hook, and Make root.

The buttons at the bottom of the Categories window have the following functions:

• Add - add a new category
• Delete - delete the currently selected category
• Link - link a new value to the currently selected field in the current category
• OK - save the changes to the category info file (appnodes.dat in the info subdirectory)
• Cancel - cancel the changes to category attributes
• Help - display this page of help file

Tools : Categories is most useful to (1) delete categories, (2) change category templates, and (3) change category names.

To create a new category, you will most likely want to use Create new category on the pop-up menu in the contents window. Also to determine the root and hook you will rather use Make hook and Make root on the same menu.

Here is the typical way of working with categories:

1. Select a branch in the contents window (this branch will became the root and the first hook of the newly created category)
2. Choose Create new category (Ctrl+D) on the contents pop-up menu
3. To change the default template use Tools : Categories and double click Default Template (for the current category you can also use Tools : Options : Appending : Default Item Template)
4. To change a category (e.g. to start working with Chemistry instead of Geography), choose the new category in the category combo-box on the toolbar (the leftmost combo-box)

Once you understand the concept of the category, it will become very easy to manage a large number of items belonging to entirely different areas of knowledge

Frequently Asked Questions

(Vidar Garlie, Norway, Mar 18, 1999)
Question:
When I go to the contents window, select a category branch and click Ctrl+A, the template of this category is not used! Can you help?
Answer: