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Step 3: Creating a New Theory

 

First you must create a new theory segment. This will contain the definitions and theorems you create. To do this, go to the File menu and select the New Theory entry. A dialog box will appear. You should now type btree into the entry field.

 
Figure: Creating a New Theory

After you press Ok, TkHol will ask you whether you want it to ``create and manage mk_btree.sml'' for you. This is because TkHol has some fairly simple mechanisms to automatically manage your theory scripts. Theory scripts are the ML programs which are the record of your work, and which can remake your definitions and reprove your theorems at a later date. In a very real sense thay are the record of your HOL work.

Answer yes to this question for now, although as you become a more experienced HOL user you may want to manage your theory scripts for yourself.

The new theory has now been created. A new window will appear, and the theory viewer will have changed its view to the theory btree. The new window is a ``script browser'', which gives you a view of the script you have now created. At the moment this has only one action - the creation of the new theory. For the moment you should iconfiy this window or place it to one side.

 
Figure: The Script Editor for the new theory



Donald Syme
Fri Sep 1 04:00:07 BST 1995