NL Semantics Meaning Representations

1. NL SemanticsMeaning Representations Read J & M Chapter 14.

2. Why Meaning? • Meaning is a function of the application: • Front end to an application system: • Find me a cheap Italian restaurant. • What’s the weather in Austin. • Drive to Houston. • Text retrieval: Suppose we want fad gifts to match: • pet rock • cabbage patch dolls • latest trends for Christmas • MT

3. Representing the Meaning of Sentences John saw Bill. John has a cat. John saw Bill (another try) John has a cold. John served Bill. John served the team. John served steak. Kirby Lane serves vegetarian food. Mother’s is a vegetarian restaurant.

4. More Examples - Price Mother’s costs less than $10. Mother’s is cheap. Mother’s is on Duval. Mother’s is on the Chronicle’s list.

5. More Examples – Eating Restaurants • I want to eat Italian food. • I want to eat someplace that serves Italian food.

6. More Examples – Mary and Sue • Mary is Sue’s sister. • Sue is Mary’s sister.

7. More Examples – Possessives Mary is Sue’s sister. Mary read Sue’s book. Mary washed her hands. Maryland’s capital is Annapolis.

8. More Examples - Adjectives cheap restaurant modest mansion former friend fake gun We can try to figure out the correct semantic relationship or we can introduce a vague relation and work it out later.

9. More Examples – Vague and Relative Words • Agnes is a big cat. • Agnes is a big tiger. • Agnes is big. • Mary is stunning. • Susan is old-fashioned.

10. More Examples – Relating Objects leather jacket riding jacket winter jacket letter jacket

11. More Examples – Events • I ate lunch. • I ate a turkey sandwich. • I ate in my office. • I eat lunch every day. • I eat lunch at noon.

12. More Examples – Quantifiers and Logic Everyone ate a cookie. The team built a house.

13. Sentences that Aren’t Declarative 1. Does John have a cat? 2. Close the window. 3. Can you close the window? 4. Do you sell pretzels? 5. I need to know whether you sell pretzels. Language as action. The theory of speech acts. But what about other applications like MT?

14. Representing Belief • Borders is open until midnight. • Mary believes that Borders is open until midnight. • Borders is the biggest bookstore in town. • Conclude, from 1 and 3, that The biggest bookstore in town is open until midnight. • Can we conclude that Mary believes that the biggest bookstore in town is open until midnight.