Tutorial 15: Elementary derivations in predicate logic

Logical System

2013

The Tutorial

The propositional rules of derivation carry over unchanged into Predicate Logic

 

 


Exercises to accompany Predicate Tutorial 5

Exercise 1 (of 1).

 

The propositional rules of inference are used unchanged in predicate logic.

Derive

a) Fa ∴ ∼ ∼ Fa
b) ∴ ∼ (Fb∧ ∼ Fb)
c) ∼ Fm∧ ∼ Gn∴ ∼ (Fm∨Gn)
d) (Fa∧Fa)∨(Gb∧Gb)∴ Fa∨Gb
e) Fb⊃(Ga⊃Hc), Fb⊃Ga ∴ Fb⊃Hc
f) Fa∨Gb, Gb⊃Hd ∴ ( ∼ Fa⊃Hd)
g) (Fa⊃Gb)∧(Gb⊃Fa) ∴ Fa≡Gb


Should you wish to use the Deriver application for this, see Exercises for Easy Deriver using the Deriver Web Application [Gentzen] . Or, more directly, Deriver20 [Gentzen]. Good advice is: start these tutorials without it, but if you get to the point of wishing to save some work, then switch to the Deriver Web Application.

Then either copy and paste the above formulas into the Journal or use the Deriver File Menu to Open from URL... with this address https://softoption.us/test/easyDeriver/CombinedExercisesEasyDGentzen.html .