Typing Shortcuts for the Assumption

Here are a couple of hints for making enties in an assumption's statement field. The first just fills in the assumption for you (sometimes!), while the second removes an assumption and un-terminates a subderivation!

1. If you are making an assumption as you work toward your ultimate goal, type a single quote into the sentence field. For example, if you are asked to derive '~[A&(B>~L)]', then type an 'A' for the justification in the first line after the premises and type the single quote mark in the sentence field.
   
   
   
   The compluter will read this as and assumption of 'A&(B>~L)':
   
   
   
   
   
   
2. If you have terminated a subderivation and then find you've made a mistake, as in this example:
   
   
   
   Here, you terminated the subserivation too soon. Just type an asterisk in place of the assumption:
   
   
   
   Press TAB and you can restart the subderivation and finish it when you want:
   
   
   
   You can even eliminate the assumption altogether. And you can eliminate all the text on line 5.