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Mathematical Methods in Linguistics. Basic Concepts of Set Theory.

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Presentation on theme: "Mathematical Methods in Linguistics. Basic Concepts of Set Theory."— Presentation transcript:

1 Mathematical Methods in Linguistics

2 Basic Concepts of Set Theory

3 FST - Torbjörn Lager, UU 3 What Is a Set? zAn abstract collection of distinct object (its members) zCan have (almost) anything as a member, including other sets zMay be small (even empty) or large (even infinite)

4 FST - Torbjörn Lager, UU 4 Specification of Sets zList notation (enumeration) zDiagram zPredicate notation zRecursive rules zFor an example, see page 9 in MML

5 FST - Torbjörn Lager, UU 5 Identity and Cardinality zIdentity y{Torbjörn Lager} = {x | x is the teacher in C389} zCardinality y|A| means "the number of elements in the set A"

6 FST - Torbjörn Lager, UU 6 The Member and Subset Relations za  A means "a is a member of the set A" zA  B means "every element of A is also an element of B" zA  B means "every element of A is also an element of B and there is at least one element of B which is not in A" za  B means a  B does not hold zA  B means A  B does not hold

7 FST - Torbjörn Lager, UU 7 Powerset zThe powerset of a set A is the set of all subsets of A zE.g the powerset of {a,b} is {{a,b},{a},{b},Ø}

8 FST - Torbjörn Lager, UU 8 Union and Intersection zThe union of two sets A and B, written A  B, is the set of all objects that are members of either the set A or the set B (or both) zThe intersection (sv: "snittet") of two sets A and B, written A  B, is the set of all objects that are members of both the set A and the set B

9 FST - Torbjörn Lager, UU 9 Difference and Complement zThe difference between two sets A and B, written A-B, is all the elements of A which are not also elements of B zThe complement of a set A and B, written A', is all the elements which are not in A zA complement of a set is always relative to a universe U. It also holds that A' = U-A

10 FST - Torbjörn Lager, UU 10 Set Theoretic Equalities zSee page 18 in MML

11 Relations and Functions

12 FST - Torbjörn Lager, UU 12 Ordered Pairs and Cartesian Products zThe Cartesian product (sv: "kryssprodukten") of A and B, written A  B, is the set of pairs such that x is an element in A and y is an element in B

13 FST - Torbjörn Lager, UU 13 Functions: Domain and Range rop tro meta jul ful mat ta få feg be klo se Domain 4 3 2 Range 5 6 1

14 FST - Torbjörn Lager, UU 14 A Function zA set of pairs zEach element is in the domain is paired with just one element in the range zA subset of a Cartesian product A  B can be called a function just in case every member of A occurs exactly once a the first element in a pair

15 FST - Torbjörn Lager, UU 15 Functions (cont'd) rop tro meta jul ful mat ta få feg be klo se Domain 4 3 2 Range 5 6

16 Properties of Relations page 39-53 in MML this part is optional

17 Lecture 2: Logic and Formal Systems

18 FST - Torbjörn Lager, UU 18 Basic Concepts of Logic and Formal Systems

19 FST - Torbjörn Lager, UU 19 Statement Logic

20 FST - Torbjörn Lager, UU 20 Predicate Logic

21 Lecture 3: Knowledge and Meaning Representation

22 Lecture 4: English as a Formal Language

23 FST - Torbjörn Lager, UU 23 Compositionality

24 FST - Torbjörn Lager, UU 24 Lambda Abstraction

25 Lecture 5: Finite Automata, Regular Languages and Type 3 Grammars

26 Lecture 6: Pushdown Automata, Context Free Grammars and Languages Lecture 6: Feature Structures and Equations

27 Lecture 7: Feature Structures and Unification-Based Grammars


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