Logical System
12/28/20

You may have derivations of your own that you wish to try. Just type, paste, or drag and drop, them into the panel, select your derivation, and click 'Start from selection'.

[Often copy-and-paste won't work directly from a Web Page; however, usually drag-and-drop will work!]

You will need to use the correct logical symbols. Here they are

F ∴ F ∧ G ∼ ∧ ∨ ⊃ ≡ ∀ ∃ ∴

And the right syntax (the premises separated by commas and then a 'therefore' followed by the conclusion).

So, a selection needs to have a form similar to this

F⊃G,G⊃H∴F⊃H

Type, paste, or drag and drop, text into the journal, select your derivation, and click 'Start from selection'. [Often copy-and-paste won't work directly from a Web Page; however, usually drag-and-drop will work!]

You will need to use the correct logical symbols. Use the palette above or

∼ ∧ ∨ ⊃ ≡ ∀ ∃ ∴

And the right syntax (the premises separated by commas and then a '∴' followed by the conclusion).
So, a selection needs to have a form similar to this

F⊃G,G⊃H∴F⊃H

If you decide to use the web application for the exercises you can launch it from here Deriver [Gentzen] — username 'logic' password 'logic'. Then either copy and paste the above formulas into the Journal or use the Deriver File Menu to Open Web Page with this address https://softoption.us/test/Deriver/CombinedTutorialsGentzen.html .

Preferences

You will need to set some Preferences for this.

• set identity to true (and that will give you the identity rules)
• set firstOrder to true (to get first order theories)
• set setTheory to true (if you are going to do set theory)
• and  you can check that the parser is set to gentzen.