Semantics Continued

1
Semantics Continued

• Meaning Relationships
• Entailments
• Maxims of Conversation

2
Semantic relationships

• The semantic relationships we will discuss here
  are
• Hyponyms X is a subset of Y
• Synonyms X is similar to Y
• Antonyms X is opposite of Y
• Homonyms X sounds/spelled like Y
• Entailment X is entailed by Y (If X, then Y)

3
Hyponyms

• X is a hyponym of Y if X is a subset of Y.
• For example, consider the two words bird and
  parakeet.
• Tweety and Polly are parakeets.
• The current set of parakeets contains these two
  members.
• The current set of bird contains at least these
  two members, possibly others.
• Parakeet is a subset of bird, so parakeet is a
  hyponym of bird.

4
Hyponyms

• Hyponymy can be seen as the loss of specificity.
• It involves moving from more specific to more
  general.

5
Synonyms

• Two words are synonymous if they share the same
  meaning.
• Rarely are word meanings 100 identical
• Used in different contexts, have different
  connotations sofa vs. couch
• While it is difficult to find two exactly
  identical words, there are examples of synonyms
  in our everyday language

6
Synonyms

• cease/stop
• dog/canine
• quick/rapid
• There is no dog that is not a canine.
• Every couch is also a sofa.
• If you cease, you also stop

7
Antonyms

• In its barest form, antonymy refers to the
  condition of being opposites.
• Complementary/contradictory
• Complete/incomplete, married/single
• Must be one or the other
• Relational opposites/contraries
• Over/under, doctor/patient, stop/go
• Can be neither, represent symmetrical
  relationships
• Scalar antonyms/gradable pairs
• Hot/cold, big/small, tall/short
• Can be neither, represent extremes on a scale

8
Antonyms

• Complementary/contradictory pairs
• Given X and Y, every entity in the world is
  either in Xs set or in Ys set, but never in
  both.
• married/unmarried
• visible/invisible

9
Antonyms

• Relational opposites / Contraries
• Given X and Y, everything in the world is in Xs
  set, in Ys set, or in neither set, but never in
  both sets.
• over/under
• An object can be over or under another, but never
  both. It could also be NEXT TO another object.
• married/bachelor
• A man can be married or a bachelor, but not both.
  He could also be a divorcé or a widower.

10
Antonyms

• Scalar antonyms/Gradable pairs
• Given X and Y, X and Y fulfill the conditions for
  being relational opposites but in addition can be
  interpreted as endpoints on some scale.
• good/bad
• hot/cold
• strong/weak
• A good test for this kind of relationship is the
  potential use of the modifier quite.

11
Homonym

• Source of much lexical ambiguity
• Different words with the same form but with
  different meanings.
• Homonym sounds spelled the same
• pen/pen, pool/pool
• Homophone sounds the same
• tale/tail, knight/night, pen/pen, tier/tear
• Homograph spelled the same
• tear ????/tear ????, pen/pen, lead lId/lead
  lEd

12
Entailments

• If A, then B (but not necessarily vice versa)
• 1. If something is an A, it must also be a B,
  too.
• 2. If something is not a B, then it cannot be an
  A.

A mare B horse C animal
C
C
B
A
A
13
Semantic Entailments

• Inferences
• The sheriff killed Jesse.
• Entails Jesse is dead.
• Semantic decomposition
• kill cause someone to die
• die to become dead
• The sheriff killed Jesse, but Jesse is still
  alive.
• Alive not dead

14
Pragmatics

• Want to see a movie tonight?
• I have to study.
• What do you want for your birthday?
• Well, my camera is broken

15
Maxims of Conversation

• Quantity
• Dont say more or less than is required
• Relevance
• Be relevant
• Manner
• Avoid ambiguity, be brief and orderly
• Quality
• Be truthful