?????
??
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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?384322 B.C.???? ??????
·F. Bacon?15611626?????
·R. Descartes?1596-1650???????????????????
·Leibniz?16461716?Leibniz????????????????????????
·G. Boole?18151864????????????????Boolean algebra?
·G. Frege?18481925?1879??Begriffsschrift???????????????????????PK?
·G. Peano?18581932??????????PA?Peanos Arithmatic??
·G. Cantor?18451918???Set Theory????????????
·B. Russell?18721970?????Whitehead??Principia Mathematica?3????????????
·D. Hilbert?18621943??????????????????????????
·A. Turing?19131954???Turings 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?
?
????
?
?i.e., In BNF?V=v|V??
?1.2??????individual constants?
?
?????
?
?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
???
?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??????????
????????????????????????????????????????????