Logical System

2013

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 ∼ & ∨ ⊃ ≡ ∀ ∃ ∴ (or use the palette to produce them)

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

'a..v' are constants, 'w..z' are variables, and you can use subscripts on the constants, variables, functors, and predicates. So here is an example of more advanced syntax.

(∀x₁)(Fx₁⊃Gx₁),(∀x)(Gx⊃Hf(a))∴(∀y)(Fy⊃Hf(a))

If you decide to use the web application for the exercises you can launch it from here Deriver[Bergmann] — 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/easyDeriver/CombinedExercisesEasyDBergmann.html .

Preferences

You may need to set some Preferences for this.

• you can check that the parser is set to bergmann.