The Logic Resource Center
Public Alpha
Systems
Open options
Systems
The Logic Resource Center
Public Alpha
Systems
Open options
Systems
Double Negation Introduction
Constants
¬
Systems
OLI
Start a Problem
→
Double Negation Introduction
i.
ϕ
⋮
ii.
¬
¬
ϕ
DNI: i
Forward
Select an available formula
Click "Apply"
Backward
Select a goal double negation
Click "Apply"
Preview shown for the
Point And Click
derivation type in the
OLI
system
