国产91麻豆一区二区久久久

【标题】Past, Present and Future: the logic and philosophy of Arthur Prior

【时间】5月28日下午4点－6点

【地点】北大理教311

【主讲人】Dr Jeremy Seligman （谢立民） 奥克兰大学

【主办方】北京大学新西兰中心及国产91麻豆一区二区久久久逻辑、语言及认知中心

摘要：Fascinated with the concept of pre-destination, New Zealand logician
Arthur Prior (1914-1969) initiated the first systematic investigation into the  
logic of time. His clarity of thought and sharp distinctions are a model of
philosophical enquiry and many of his ideas subsequently became a theoretical  
foundation for research on time in philosophy, linguistics and computer science.
This lecture will be a gentle introduction to some of these ideas, against
the background of the life of “an exuberant, playful man of seemingly
inexhaustible vitality” (Copeland 2007) held in celebration of his centenary year.  

16:00 - 17:00 Prior Memorial Lecture by Dr Jeremy Seligman  

17:10 - 18:00 Casual workshop on postgraduate studies in New Zealand with ass
istance from Auckland University representatives and New Zealand Centre staff
~ tea and biscuits provided ~  

This event made possible by collaboration between the New Zealand Centre(http
://nzc.sfl.pku.edu.cn/index.html) and the Peking University Centre for Logic,
Language and Cognition (http://www.phil.pku.edu.cn/cllct/).

For more information about New Zealand Centre Visiting Fellow Dr Jeremy Selig
man, you can visit his official homepage: http://www.arts.auckland.ac.nz/people/jsel014

谢立民博士在此报告前还有一场技术性的逻辑学报告，也欢迎感兴趣的同学参加：

【时间】5月28日下午3点10分－3点50分
【地点】北大理教311

Secret tweets and network discovery

You are a secret agent with a secret $S$ that you would like to transmit to a
fellow agent $a$ unobtrusively using a very public network like Twitter. Any
information you tweet will be received by your followers on the network. You
correctly assume that they will send the message on to their followers (retw
eet it) if and only if it does not conflict with any information they already
possess. With luck,your message will be tweeted through the network until it
eventually reachers $a$. Under what conditions is it possible for you to con
vey $S$ to $a$ in this way,without other agents in the network learning this
information? Clearly,you cannot tweet $S$ itself,but if,for example,$a$ is th
e only agent to knows that $K$ then the message `if $K$ then $S$’ may work,i
f there is a suitable path from you to $a$. To know whether you can succeed o
r not and what to tweet,you need to know something about the network and the
information already possessed by the other agents. But you can learn somethin
g about this with a test tweet. If,for example,you know that you have two fol
lowers $b$ and $c$ and only $b$ believes $P$ and then you tweet the message $
eg P$ then if,after a certain length of time,someone tweets $P$ to you,you k
now that there is a loop back to you via $c$. This talk will report on recent
joint work on these and similar questions with Mostafa Raziebrahimsaraei.