?????

—— ??

???????????

???

2003?5?????101????

 

§1. ??????

§2. ????????

§3. ??????????

§4. ???????

 

§1. ???????Symbolic Logic?

Definition 1.1?Pierce?

????????????????????????????????

 

Definition 1.2?Longman???

Symbol=a sign, shape, or object which represents a person, idea, value, etc.

 

Definition 1.3?Hjelmslev?

??=???expression?????meaning?

????????????????????????

 

??=??????

?????????????????????????????????

??????????????????—???????????

 

????

·Aristotle?384—322 B.C.????  ??????

·F. Bacon?1561—1626?????

·R. Descartes?1596-1650???????????????????

·Leibniz?1646—1716?Leibniz????????????????????????

·G. Boole?1815—1864????????????????Boolean algebra?

·G. Frege?1848—1925?1879??Begriffsschrift???????????????????????PK?

·G. Peano?1858—1932??????????PA?Peano’s Arithmatic??

·G. Cantor?1845—1918???Set Theory????????????

·B. Russell?1872—1970?????Whitehead??Principia Mathematica?3????????????

·D. Hilbert?1862—1943??????????????????????????

·A. Turing?1913—1954???Turing’s Machine???????????Computation?????

·K. Gφdel?1906-1978?PK?????? PA???????

 

???2000?????TIMES???????20???????the greatest mind?Turing?Gφdel???????????????

 

 

§2. The 1st order predicate calculus

??????????????????????????

??????

?1?????

?1.1??????individual variables?

?1.1.1?v???

?1.1.2??x????????

?1.1.3????????

?i.e., In BNF?V=v|V??

?1.2??????individual constants?

?1.2.1?c???;

?1.2.2??d????????

?1.2.3???????.

?2?????functions?

?2.1?????f0?f1?f2

?2.2?????g0?g1?g2

????f???arity?>0?

?3?????predicates?

?3.1?????p0?p1

?3.2?????q0?q1 ??????????

????p???arity?>0?

?4????propositions?

?4.1?????P0?P1

?4.2?????T?F

?5?????Connectives???????.

?6????quantifiers?  ?

?7?????????· ?[ ?]?{?}

???????????????????syntax?

??2.1??,term?

?1?????;

?2??f?n????t1?…?tn????f?t1,…,tn????

?3??????

??2.2?????,atomic formula?

?1?????????

?2??p?n????t1?…?tn????p?t1,…,tn?????

?3?????????.

??2.3???,formula?

?1?????????

?2??????????;

?3???????????????;

?4??????x???????????;

?5???????

???????????????????sentence??

Frege??????????PK?

PK??????axiom??????rule???????PK?????

???|—????|—???????????????????

??????????????????????????

???MP??|—(??????),

PK?????consistent?????complete??

??????????(syntax)??????????semantics??

 

§3. ??????????interpretation?

????????????????????????????

?1????????????,?????1??, ??

?2??????????????mapping????+ .

?3?????????????????????“=”???“??”.

?4????????????, ??“????”.

?5????T?F?????. PK?2-valued logic?2?????

?6???????it is not the case that??????and????????or?;

????imply??????equivalent?

?7????for all?????for some?

???greaterthan?x,y??,??greaterthan?x,y????x??y???????????x??y?x??y?

??is true or  is not true?.

????????(powerful)???????????expressive power?????B.Russell????????????? ???????????????????????????????????????????????????????????????????????????????????????.?????????1980s???????????? Prolog??????

 

 

§4. ????????Understanding of natural languages in ?

???????????????????????????????????????????????????????limitation??

?1?                        ????????????

?2?                        To be or not to be?????“x?????”???????????????????“????”??????

????????????tense logic???????

??????????????????????????????

 

?3????????????????????????

?3.1???p?q???q?p?????????????????????????

?3.2?????????????????????,

“????????”??p???  q????,????p?q????p?q??

?3.3???????????“?…?”???????“?…?”???????????????????????

 

?4?????????arity

?????????????…?…?…?3????

 

?5???????????????????????????????????Russell???????????????????descriptor ???x.(x)=??????(x)??x.

 

?6???????????, ???????????????.

????????????????.  1960s????Fuzzy Logic?????.

 

?7????????????????????????????????????

?7.1????????????,????????.

?7.2????????????????

?7.3?All that glitters is not gold.

?glitter?x?gold?x??

?7.4?????? ?????????,????“?”???????

?7.5??????????????“?”???

?7.6????????????????????????????

“?”?“?”?“?”???

?7.7????????

?7.8????????????

???????????????????????????

 

?8??????????????????????????????

????????A man, a plan, a canal: Panama

?????????????????????

??????????????

 

·?????

??????????????????????????????7??????????????????????

?1??????????2???????3??????4??????????

????????????????????????????????????????????