- 1、本文档共14页,可阅读全部内容。
- 2、有哪些信誉好的足球投注网站(book118)网站文档一经付费(服务费),不意味着购买了该文档的版权,仅供个人/单位学习、研究之用,不得用于商业用途,未经授权,严禁复制、发行、汇编、翻译或者网络传播等,侵权必究。
- 3、本站所有内容均由合作方或网友上传,本站不对文档的完整性、权威性及其观点立场正确性做任何保证或承诺!文档内容仅供研究参考,付费前请自行鉴别。如您付费,意味着您自己接受本站规则且自行承担风险,本站不退款、不进行额外附加服务;查看《如何避免下载的几个坑》。如果您已付费下载过本站文档,您可以点击 这里二次下载。
- 4、如文档侵犯商业秘密、侵犯著作权、侵犯人身权等,请点击“版权申诉”(推荐),也可以打举报电话:400-050-0827(电话支持时间:9:00-18:30)。
查看更多
Introduction to Weak Methods in Theorem Proving 13.1 The General Problem
1Automated Reasoning
13
13.0 Introduction to Weak
Methods in Theorem
Proving
13.1 The General Problem
Solver and Difference
Tables
13.2 Resolution Theorem
Proving
13.3 PROLOG and
Automated Reasoning
13.4 Further Issues in
Automated Reasoning
13.5 Epilogue and
References
13.6 Exercises
2
Chapter Objective
? Learn about general-purpose theorem proving
in predicate calculus.
3
The problem
? Given:
a knowledge base (a set of sentences)
? Prove:
a sentence
Formally,
? Given:
a Knowledge Base (KB),
a sentence α
? Show whether:
KB |= α (does KB entail α ? Or
does α follow from KB ?)
4
The tool
? Modus ponens
KB: p → q
p
question: q
answer: yes
{p → q, p} |= {q}
? We can form arbitrarily long “chains” of
inference to prove a sentence
? We can use forward or backward reasoning
5Example
? If Mary goes to a party, Jane also does.
If Jane goes to a party, she cannot study.
If Jane cannot study, she fails.
Mary went to a party.
? Can we prove:
Jane will fail.
6
Example
? If Mary goes to a party, Jane also does.
M J
If Jane goes to a party, she cannot study.
J C
If Jane cannot study, she fails.
C F
Mary went to a party.
M
? Can we prove:
Jane will fail.
F
Does {M → J, J → C, C → F, M} entail {F}?
7
Example
1. M → J
2. J → C
3. C → F
4. M
Modus ponens on 1 and 4:
5. J
Modus ponens on 2 and 5:
6. C
Modus ponens on 3 and 6:
7. F proven! 8
Another tool
? Modus tollens
KB: p → q
?q
entails ? p.
? So, a theorem proving process involves
applying such rules until the desired sentence
is proven.
? We call this a “proof” because the rules we
use are sound (correct).
9Using modus ponens
? solves a lot of practical problems and is fairly
efficient in terms of “searching” for a proof.
? Unfortunately, fails to prove some sentences
which should be entailed by a KB (it is
incomplete)
10
Example
If Mary goes to the party, Jane also will.
M J
If Mary does not go to the party, Jane will.
?M J
{ M → J, ?M → J} should entail {J} because
either M is true, or ?M is true and either way J
您可能关注的文档
- GRE AW ISSUE 所有高频题详细提纲.pdf
- gstreamer媒体框架.pdf
- GRE范文及赏析-Argument22-智课网.pdf
- GRE范文及赏析-Argument32-智课网.pdf
- GT21L16S2Y用户手册V32.pdf
- GT21L16M2Y2-S字库芯片完整资料.pdf
- guideline on stability testing-emea.pdf
- GT-I8150_Schematics_110907.pdf
- Guidelines for diagnosing, prevention and treatment of osteoporosis in Asia.pdf
- GRE逻辑支持题之A与B的联系-智课教育旗下智课教育.pdf
文档评论(0)