The Logic Resource Center

The Logic Resource Center

Public Alpha

The Logic Resource Center

Public Alpha

© 2025 The Logic Resource Center, LLC

Conjunction Introduction

Conjunction Introduction is probably one of the least often denied classical rules of inference.

Constants: &
Systems: LRC_F OLI The Logic Book LRC LRC_P LRC_O

Start a Problem →

Conjunction Introduction

i

i.

ϕ

ii

ii.

ψ

⋮

i, ii

iii.

ϕ&ψ

&I: i, ii

Foward

Enter the conjunction you wish to add
Cite the lines of which it is the conjunction
Hit Return

Preview shown for the Typed Forward Strict derivation type in the LRC_F system