## Abstract

We have presented efficient syntax directed presentations of two subclasses of PTS:

the semi-full systems, via the ⊢

the functional systems, via the ⊢

The only remaining defect in these presentations lies in the possible failure of tests for conversion in the application rule. Thus for normalizing functional and semi-full systems, everything has been said.

For non-functional systems the situation is less clear. We know of no a priori bound on the amount of reduction necessary to correctly type λ-abstractions, so we must be content with the collective completeness of the family of syntax directed systems ⊢

We have made little impact on the Expansion Postponement problem, which we leave as future work. We can however bask in the relative peace of mind gained from the machine-checked presentation of most (i.e. those not concerning schematic judgments) of the above results.

the semi-full systems, via the ⊢

_{sdsf}relationthe functional systems, via the ⊢

_{f}relationThe only remaining defect in these presentations lies in the possible failure of tests for conversion in the application rule. Thus for normalizing functional and semi-full systems, everything has been said.

For non-functional systems the situation is less clear. We know of no a priori bound on the amount of reduction necessary to correctly type λ-abstractions, so we must be content with the collective completeness of the family of syntax directed systems ⊢

_{sd−n}.We have made little impact on the Expansion Postponement problem, which we leave as future work. We can however bask in the relative peace of mind gained from the machine-checked presentation of most (i.e. those not concerning schematic judgments) of the above results.

Original language | English |
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Title of host publication | Types for Proofs and Programs. TYPES 1993 |

Publisher | Springer |

Pages | 19-61 |

Number of pages | 43 |

ISBN (Electronic) | 9783540484400 |

ISBN (Print) | 9783540580850 |

DOIs | |

Publication status | Published - 1994 |

### Publication series

Name | Lecture Notes in Computer Science |
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Volume | 806 |

ISSN (Print) | 0302-9743 |

ISSN (Electronic) | 1611-3349 |