NL SemanticsMeaning Representations

Read J & M Chapter 14.

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

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.

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.

More Examples – Eating Restaurants

1. I want to eat Italian food.

2. I want to eat someplace that serves Italian food.

More Examples – Mary and Sue

1. Mary is Sue’s sister.

2. Sue is Mary’s sister.

More Examples – Possessives

Mary is Sue’s sister.

Mary read Sue’s book.

Mary washed her hands.

Maryland’s capital is Annapolis.

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.

More Examples – Vague and Relative Words

1. Agnes is a big cat.

2. Agnes is a big tiger.

3. Agnes is big.

4. Mary is stunning.

5. Susan is old-fashioned.

More Examples – Relating Objects

leather jacket

riding jacket

winter jacket

letter jacket

More Examples – Events

1. I ate lunch.

2. I ate a turkey sandwich.

3. I ate in my office.

4. I eat lunch every day.

5. I eat lunch at noon.

More Examples – Quantifiers and Logic

Everyone ate a cookie.

The team built a house.

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?

Representing Belief

1. Borders is open until midnight.

2. Mary believes that Borders is open until midnight.

3. 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.