List of Authors | ix |

Forward | xi |

Author's Preface | xv |

**Chapter 1: Introduction** | 1 |

Motivation | 3 |

Responding to the Critics | 11 |

The Symbol Grounding Problem | 20 |

Contents of the Book | 28 |

**Chapter 2: Knowledge Representation** | 31 |

Overview | 33 |

Informal Languages | 35 |

Frames | 38 |

Description Logic | 41 |

Propositional and Predicate Logic | 47 |

First-Order Logic | 53 |

Higher-Order Logics | 55 |

First-Order Logic in SUO-KIF | 56 |

SUO-KIF Details | 58 |

Conversion to First-Order Logic | 61 |

Exercises | 68 |

**Chapter 3: Ontologies (in the Broadest Sense)** | 69 |

Introduction | 71 |

WordNet (and Why it's not an Ontology) | 71 |

Digression: Ontology Development Pitfalls | 78 |

**Chapter 4: Suggested Upper Merged Ontology** | 83 |

Overview | 86 |

Validation | 89 |

Principles of Construction | 92 |

Digression - Open Research | 93 |

SUMO History | 94 |

SUMO Overview | 101 |

SUMO's Eleven Modules | 105 |

Lower Level Ontologies | 109 |

Ontological Issues | 111 |

Ontology Code Management | 118 |

SUMO Details and Examples | 120 |

Semiotics Content | 147 |

Exercises | 154 |

**Chapter 5: SUMO and the WordNet Mappings** | 157 |

Overview | 159 |

Interpreting Language | 164 |

Global WordNet | 166 |

The Interlingual Index | 166 |

Arabic and Filipino Wordnets | 168 |

**Chapter 6: Knowledge Engineering Tools** | 171 |

Introduction | 173 |

Language Generation | 175 |

Browsing and Display | 179 |

Analysis and Debugging | 182 |

Inference | 184 |

Higher-Order Logic | 192 |

Mapping, Merging and Translation | 194 |

Working with Sigma and SUMO | 195 |

Example Application | 197 |

Browsing and Editing | 201 |

Sigma Tutorial | 202 |

Exercises | 214 |

**Chapter 7: Using SUMO for Inference** | 215 |

Overview | 217 |

Inference | 218 |

Example Inference | 220 |

Proof Presentation | 222 |

Resolution Theorem Proving Example | 223 |

Normalization Algorithm | 230 |

Refutation Algorithm | 232 |

**Chapter 8: Controlled English to Logic Translation** | 235 |

Introduction | 237 |

Simple Parsing and Interpretation | 239 |

Issues in Translation | 241 |

CELT Components | 248 |

**Chapter 9: An Application: Extending SUMO with Wikipedia** | 249 |

Introduction | 251 |

Related Work | 251 |

General Comparison of the Knowledge Sources | 253 |

Integration of Entities | 255 |

Integrating Factual Knowledge | 262 |

Semantics of Terms in Ontologies | 266 |

Conclusion | 267 |

Summary and Conclusions | 269 |

Answers to the Exercises | 271 |

Acknowledgments | 275 |

References | 279 |

Index | 297 |