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Newsletter Feb. 7, No. 15
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Subject: Newsletter Feb. 7, No. 15
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From: csli@csli.stanford.edu
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Date: Wed 6 Feb 1985 17:20:59-PST
C S L I N E W S L E T T E R
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February 7, 1985 Stanford Vol. 2, No. 15
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A weekly publication of The Center for the Study of Language and
Information, Ventura Hall, Stanford University, Stanford, CA 94305
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CSLI ACTIVITIES FOR *THIS* THURSDAY, February 7, 1985
12 noon TINLunch
Ventura Hall Excerpts from Charles Bigelow's ``Principles of
Conference Room Structured Font Design for the Personal Workstation''
and Fernand Baudin's
``Typography: Evolution + Revolution''
Discussion led by David Levy
2:15 p.m. CSLI Seminar
Redwood Hall ``Reasoning About Actions and Processes''
Room G-19 Michael Georgeff, CSLI
3:30 p.m. Tea
Ventura Hall
4:15 p.m. CSLI Colloquium (See the notice below)
CCRMA ``From Sound to Score: Computerized
Transcription of Music''
Bernard Mont-Renard, Center for Computer Research
in Music and Acoustics (CCRMA)
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CSLI ACTIVITIES FOR *NEXT* THURSDAY, February 14, 1985
12 noon TINLunch
Ventura Hall ``Belief, Awareness, and Limited Reasoning''
Conference Room Ronald Fagin, IBM San Jose Research Laboratory
(Abstract on page 2)
2:15 p.m. CSLI Seminar
Redwood Hall ``Logic and Functional Programming''
Room G-19 Joseph Goguen, CSLI
Discussion will be led by Fernando Pereira
(Abstract on page 2)
3:30 p.m. Tea
Ventura Hall
4:15 p.m. CSLI Colloquium
Redwood Hall ``Against Theory''
Room G-19 Steve Knapp and Walter Benn Michaels,
English Department, UC Berkeley
(Abstract on page 2)
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COLLOQUIUM NOTICE
Unfortunately, since this week's colloquium cannot be held at Redwood Hall,
it can only accommodate 25 people and is already full.
Page 2 CSLI Newsletter February 7, 1985
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ABSTRACT OF NEXT WEEK'S TINLUNCH
Possible-worlds semantics for knowledge and belief do not seem appropriate
for modelling human reasoning since they suffer from the problem of what
Hintikka calls ``logical omniscience''. This means that agents are assumed
to be so intelligent that they must, in particular, know all valid
formulas. Moreover, each agent's knowledge is also closed under deduction,
so that if an agent knows p, and if p logically implies q, then the agent
must also know q. Unfortunately, this is certainly not a very accurate
account of how people operate! People are not logically omniscient for
several reasons, including (1) Lack of awareness: how can someone say that
he knows or doesn't know about p if p is a concept he is completely unaware
of? (2) People are resource-bounded: they simply lack the computational
resources to deduce all the logical consequences of their knowledge. (3)
People don't focus on all issues simultaneously: it is possible for a
person to have distinct frames of mind, where the conclusions drawn in
distinct frames of mind may contradict each other. Some new logics for
belief and knowledge are introduced which model these phenomena, so that,
in particular, agents need not be logically omniscient. This talk
represents joint work with Joe Halpern. --Ronald Fagin
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ABSTRACT OF NEXT WEEK'S SEMINAR
``Logic and Functional Programming''
We begin by reviewing what logic and functional programming are, indicating
basic aspects of their programming styles, applications and implementations.
We then show how to enrich logic programming with some features of current
interest in programming methodology, maintaining both logical rigor and
efficient implementation. The first and most important feature is
functional programming; full logical equality provides an elegant way to
combine the power of logic programming (including logical variables,
pattern matching and automatic backtracking) with functional programing
(supporting functions and their composition, as well as strong typing and
user definable abstract data types). An interesting new feature that
emerges here is a complete algorithm for solving equations containing
logical variables; this algorithm uses ``narrowing,'' a technique from the
theory of rewrite rules. The underlying logical system here is many-sorted
Horn clause logic *with* equality. A useful refinement is ``subsorts,''
which can be seen as an ordering relation on the set of sorts (usually
called ``types'') of data. Finally, we provide generic modules by using
methods developed in the specification language Clear. These features make
up a language called Eqlog; we illustrate them with a program for the
well-known Missionaries and Cannibals problem, and with some simple
examples from natural language processing. --Joseph Goguen
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ABSTRACT OF NEXT WEEK'S COLLOQUIUM
``Against Theory''
Walter Michaels and Steven Knapp, English Department, UC Berkeley
A discussion of the role of intention in the interpretation of text. We
argue that linguistic meaning is always intentional; that linguistic forms
have no meaning independent of authorial intention; that interpretative
disagreements are necessarily disagreements about what a particular author
intended to say; and that recognizing the inescapability of intention has
fatal conse- quences for all attempts to construct a theory of
interpretation.
Page 3 CSLI Newsletter February 7, 1985
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SUMMARY OF THIS WEEK'S NL4 ACTIVITIES
This week, Phil Cohen demonstrated how theorems characterizing direct
requests (one's mentioning an action) and non-specific direct requests (to
make some state-of-affairs true) could be derived from principles of
rational action. The characterizations could distinguish felicitous
requests from non-serious or insincere ones (e.g., ``go jump in the lake'',
``fly me to mars'') through general principles of action.
We will meet again Feb. 19, at 12:45 in the trailers' classroom. Cohen
will this time derive characterizations of real, teacher/student, and
rhetorical yes-no questions from the earlier ones for requesting, and
informing.
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SUMMARY OF AREA C MEETING
``Algebraic Specifications in an Arbitrary Institution''
Andrzej Tarlecki
Dept. of Computer Science, Univ. of Edinburgh
The pioneering papers on algebraic specification used many-sorted
equational logic as a logical framework in which specifications were
written and analyzed. Nowadays, however, examples of logical systems in
use include first-order logic, higher-order logic, infinitary logic,
temporal logic, and many others. Note that all these logical systems may
be considered with or without predicates, admitting partial operations or
not. This leads to different concepts of signature and of model, perhaps
even more obvious in examples like polymorphic signatures, order-sorted
signatures, continuous algebras, or error algebras. The informal notion of
a logical system for writing specifications has been formalized by Goguen
and Burstall who introduced for this purpose the notion of institution.
The first and presumably most important application of this notion is its
use in the theory of algebraic specifications. It turns out that most of
the work on algebraic specification, especially concerning specification
languages, may be done in an institution-independent way. We briefly
present a collection of simple but very powerful specification-building
operations and give their semantics in an arbitrary institution. In this
context we outline a very simple and mathematically elegant view of the
formal development of programs from their specifications. The notion of
institution is also used to formulate (and prove) some model-theoretic
results at an appropriately general level. We show how to generalize to an
arbitrary institution a Birkhoff-type characterization of quasi-varieties
as implicational classes. This result may be used to prove that Mahr and
Makowsky's characterization of standard algebraic institutions which
strongly admit initial semantics holds for arbitrary institutions
satisfying a number of technical assumptions. Finally, we briefly outline
some problems concerning the notion of institution itself. We discuss the
need for some tool for constructing new institutions and for combining
institutions (``putting institutions together''). We also indicate
possible generalization of this notion which would provide a mold for
richer semantical systems than just collections of sentences with a notion
of their truth.
Page 4 CSLI Newsletter February 7, 1985
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SUMMARY OF F-4 MEETING
``Robot Design: In Search of the Mind-Body Synapse''
Stan Rosenschein, CSLI
For purposes of the discussion, the term ``robot'' was taken refer to a
collection of (man-made) sensors and effectors connected through a computer
controller. To lend an air of reality to the discussion, a ``hands-on''
display was given of an ultrasonic rangefinder, a small CCD camera, a
battery-operated robotics kit including a motorized gripper, and a small
computer. The challenge facing the robot designer is how to assemble these
(or similar) components to build a device capable of complex and
interesting behaviors. The most complex and difficult part of the robot
design task is programming the controller. Many AI researchers have sought
to manage this complexity by developing computational abstractions based on
some version of commonsense belief-desire-intention (BDI) psychology--the
``folk'' theory of mind. In addition, they have tended to adopt a
``representationalist'' tactic in which the components of mental state
(beliefs, desires, intentions) are realized as symbolic structures to be
manipulated by the program. Another approach, one based on an abstract
correlational theory of information-bearing states in automata, was put
forward as an alternative. There was much discussion on the utility of
belief-desire-intention psychology, especially in its
``representationalist'' form, as a framework for building robots.
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TUTORIAL LECTURES ON LINGUISTICS FOR NON-LINGUISTS
The third of three sessions intended for non-linguists on Government and
Binding (Chomsky), Generalized Phrase Structure Grammar (Gazdar/Klein/
Pullum/Sag), and Lexical Functional Grammar (Bresnan/Kaplan) takes place on
February 12. The sessions are in the trailer seminar room on Tuesdays from
1:00 to 3:00 PM. Each lecturer sketches the leading ideas of one theory,
and (perhaps) contrast it with the other theories. The complete schedule
is listed below.
January 29 GB Lecture by Peter Sells
February 5 GPSG Lecture by Geoff Pullum
February 12 LFG Lecture by Joan Bresnan
Linguists are asked not to attend.
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CONFERENCE ON EVOLUTION AND INFORMATION
A conference on Evolution and Information with major support from CSLI will
be held at Stanford this April 19-21. The specific focus of the conference
will be on the use of optimality models both in biology and in the human
sciences. Papers will be contributed to the conference by biologists,
philosophers, psychologists, and anthropologists. Apart from addressing
problems and limitations of optimality models within biology, an important
aim of the conference will be to explore the relevance of biological
results, either factually or methodologically, to other areas of inquiry.
Papers to be discussed at the conference will be circulated about a month
before the meeting. Contributors will be asked to give a brief summary of
their papers at the conference sessions but papers will not be read.
Therefore, anyone who would be interested in seeing the papers in advance,
or would like any further information about the conference, should contact
John Dupre, Philosophy, Stanford University (415-497-2587, Dupre@Turing).
Page 5 CSLI Newsletter February 7, 1985
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FIRST VOLUME OF CSLI LECTURE NOTES
The first in the series of CSLI Lecture Notes has just been published.
Entitled ``Manual of Intensional Logic,'' the 75-page book by Johan van
Benthem constitutes a graduate course that the author taught in the Winter
of 1984 while at CSLI.
``Intensional Logic as understood here,'' the author writes in the
Introduction, ``is a research program based upon the broad presupposition
that so-called `intensional contexts' in natural language can be explained
semantically by the idea of `multiple reference.' ''
Unlike CSLI Reports, the Lecture Notes will be sold for a nominal fee to
defray part of production costs. The price of ``Manual of Intensional
Logic'' is $5, and it may be purchased at the Stanford Bookstore or by
writing to Dikran Karagueuzian at the Center. A 25% discount is offered to
all members of the CSLI community or to anyone ordering three or more
copies to be used for instructional purposes. California residents should
add sales tax.
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