The order in which a tree grows is important. It is usually easier to begin with the formulas which do not create new branches. These are formulas such as ones with a • main operator.
A formula is selected when its cell is outlined with shading or when it is the only cell in its row which does not have a dark background.
To decompose a formula, select it and then either double-click or press <Enter>. The decomposition editor will appear and you can build the new branches or the additions to the current branch (these are the ones to do first). Then click on Ok or press <Enter>. You will be returned to the tree, or receive an explanation of why the decomposition choice was incorrect.
If the correctly decomposed formula is immediately above a ? then the decomposition will replace it. If not, you will have to select a ? below in the tree and click on it or press <Enter> to insert the decomposition. If the decomposition belongs in more than one place, follow the same procedure for each additional ?
After a decomposition has been entered in all the branches where it belongs, the source formula can be marked with a √ . To mark it, select it and then either press <Del> or right click with the mouse. Either the √ will appear and the decomposition deleted from the insert editor or you will be told that one or more insertions are still needed. Repeat the action to delete the mark. Ctrl+L is the keyboard shortcut.
The Mark submenu inside of the Options Menu presents alternative ways to mark lines and branches.
|
Main Heading |
Sub Headings |
Keyboard Shortcut |
Comment |
| Mark | |||
| Toggle Line Mark | Ctrl+L | Switches a symbolic line between √ and no mark. | |
| Toggle Branch Mark | Ctrl+B | Switches among ? X and open |
Note: Once an X or an open have been checked and found correct, they are marked with a √. The √X and the √open cannot be changed.
Click here for a detailed discussion of Exercise T1, Part I, Number 1.