The numbers running down the left side of the window are line numbers. Those running down the right side are "From Line" numbers; that is, they tell you where the statement on the current line came from (by decomposition). Since it can be hard to tell which numbers belong to which statement, if you press the "Command" key while holding down the mouse button on a line, a broken horizontal line appears, connecting the statement to its line and "from line" numbers. In the above example, "~Pd" is on line 6 and comes from line 4.
Of course, in a more complicated tree, where the connections between the various statements are not as obvious as they are here, you might want more information about a given statement. In that case, just double click on the statement to see its whole profile-
You might also want to rearrange the branches of a tree. You can do this simply by clicking on a statement and dragging it; all of its physical descendants will follow. Or, if you prefer to rearrange only one statement without bringing along any of its descendants, just hold down the Option key while you drag-
Note those little dotted lines running vertically down the window on either side; those show where the page margins will be when the tree is printed. If you want everything on a single page, you might have to drag statements onto it, but Bertrand can print trees up to three pages wide and any number of pages long.
Some large problems can generate trees that have such a complicated branch structure that they can be almost impossible to read. That's what the "Prune" button is for. Click on it, and only the branch from which the assignment is gotten (or, if the tree closes, the longest branch) is displayed-
Click on "Restore" to restore the tree to its former glory.
By the way, if you forget any of these commands and don't want to search through the manual, there is this handy help window to remind you-
Click here to view yet more of Bertrand's Bells and Whistles- other Help Screens, Preferences, File Types, and Truth Tables.
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