The Logic Resource Center

Public Alpha

Systems

Public Alpha

Universal Introduction

Classically known as Universal Generalization, this principle says that if you can prove something of a genuinely arbitrary instance of a generalization then you can infer that generalization.

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

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Universal Introduction

i.

ϕ[α/γ]

⋮

ii.

∀γϕ

∀I: i

Forward

Select an available substitution instance
Enter variables when prompted
Click "Apply"

Backward

Select a goal universal quantification
Enter instantiating variable when prompted
Click "Apply"

Preview shown for the Point And Click derivation type in the LRC_P system