Propositional Exercises: Roll your own

Logical System

You can try material of your own below.

Here are a few hints

  • You have to use the right (unicode/html) logical symbols. Check Writing symbols
  • The symbols in use here are ~ & ∨ →  ≡ (so copy and paste or drag and drop these).
  • When entering from a selection, the software will take a single formula (say, A) or a comma separated list of formulas (say, A,B,C) or a possibly empty comma separated list of formulas followed by ∴ and another formula (say, A,B,C ∴ D). In the last case it will load the negation of the conclusion.
  • Just type, cut and paste, or drag and drop, whatever you wish, into the lower text box. Then make a selection and hit the Start button.

Exercise: Roll your own

If you decide to use the web application for the exercises you can launch it from here Deriver [default] — username 'logic' password 'logic'. Then either type or copy and paste desired formulas into the Journal or use the Deriver File Menu to Open Web Page with this address . Then select the desired formula(s) and Start Tree off the Actions Menu.


[If you find you need to set the Preferences for the web application (because you, or someone else, has been doing something totally different with Deriver on the computer in use),

  • set the parser to default

The title bar of the Deriver window will show you what system you are running e.g. 'DeriverDefault', 'DeriverGentzen', etc.]