IF

The constant "if" expresses the material conditional. It is a matter of some debate whether this is what you mean when you say "if".

Systems

LRC_F

Typed Forward Strict

→E: Conditional Elimination→I: Conditional Introduction

Point And Click

→E: Conditional Elimination→I: Conditional Introduction

OLI

Point And Click

→I: Conditional Introduction→E: Conditional Elimination→DefI: Conditional Introduction From Material Definition→DefE: Conditional Elimination For Material DefinitionHS: Hypothetical SyllogismMT: Modus TollensTrans: Transposition

The Logic Book

Point And Click

⊃E: Conditional Elimination⊃I: Conditional IntroductionMT: Modus TollensImpl: ImplicationHS: Hypothetical SyllogismTrans: TranspositionExp: ExportationEquiv: Equivalence

LRC

Typed Forward Strict

⊃E: Conditional Elimination⊃I: Conditional Introduction

Point And Click

⊃E: Conditional Elimination⊃I: Conditional Introduction

LRC_P

Typed Forward Strict

→E: Conditional Elimination→I: Conditional Introduction

Point And Click

→E: Conditional Elimination→I: Conditional Introduction

LRC_O

Typed Forward Strict

→E: Conditional Elimination→I: Conditional Introduction

Point And Click

→E: Conditional Elimination→I: Conditional Introduction