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␈↓ α∧␈↓Referee's report on ␈↓↓Mechanizing Temporal Knowledge␈↓ by Kenneth Kahn and G. Anthony Gorry

␈↓ α∧␈↓␈↓ αTThe␈αvalue␈αof␈αthis␈α
paper␈αas␈αa␈αcontribution␈αto␈α
artificial␈αintelligence␈αdepends␈αon␈αan␈α
issue␈αnot
␈↓ α∧␈↓discussed␈α
by␈α
its␈α
writers␈α
-␈α∞namely␈α
the␈α
extent␈α
to␈α
which␈α∞a␈α
problem␈α
involving␈α
time␈α
and␈α∞some␈α
other
␈↓ α∧␈↓facet␈αof␈αreality,␈αsay␈αspace␈αor␈αthe␈αownership␈αof␈αproperty␈αcan␈αbe␈αdivided␈αinto␈αparts␈αone␈αof␈αwhich␈αis
␈↓ α∧␈↓the␈α∂time␈α∂specialist␈α∂and␈α∂the␈α∞others␈α∂of␈α∂which␈α∂-␈α∂including␈α∞any␈α∂overall␈α∂co-ordinator␈α∂-␈α∂don't␈α∞know
␈↓ α∧␈↓about␈αtime.␈α My␈αown␈αopinion␈αis␈αthat␈αthis␈αcan't␈αbe␈αdone␈α-␈αand␈αtherefore␈αthe␈αtime␈αspecialist␈αisn't␈αof
␈↓ α∧␈↓much␈αuse␈α-␈αbut␈αI␈αdon't␈αwant␈αto␈αimpose␈αthis␈αopinion␈αon␈αthe␈αauthors␈αor␈αthe␈αreaders␈αof␈αthe␈α␈↓↓Journal.␈↓
␈↓ α∧␈↓It␈αseems␈αto␈αme␈αthat␈α
some␈αfacts␈αabout␈αtime␈αcan␈α
be␈αstored␈αseparately␈αfrom␈αothers␈α
and␈αco-ordinated
␈↓ α∧␈↓with␈αfacts␈αabout␈αother␈αmatters␈αby␈αa␈αgeneral␈αproblem␈αsolver␈αof␈αsome␈αkind,␈αbut␈αthat␈αthe␈αutility␈αof␈αa
␈↓ α∧␈↓specialist␈α
is␈α
doubtful.␈α Even␈α
then,␈α
some␈αof␈α
the␈α
most␈αimportant␈α
facts␈α
involve␈αboth␈α
time␈α
and␈αother
␈↓ α∧␈↓topics, e.g. facts about motion.

␈↓ α∧␈↓␈↓ αTI␈αthink␈αthe␈αauthors␈α
should␈αbe␈αrequired␈αto␈αdisuss␈α
this␈αissue␈αat␈αleast␈αbriefly.␈α
 Moreover,␈αthey
␈↓ α∧␈↓and␈αother␈αauthors␈αof␈αpapers␈αsubmitted␈αto␈αthe␈α␈↓↓Journal␈↓␈αshould␈αbe␈αrequired␈αto␈αexplicitly␈αdiscuss␈αthe
␈↓ α∧␈↓limitations␈α
of␈αthe␈α
methods␈α
they␈αuse␈α
in␈α
the␈αpaper␈α
and␈α
the␈αlimitations␈α
of␈α
the␈αmethods␈α
they␈αuse.␈α
 Too
␈↓ α∧␈↓often␈α∩papers␈α⊃are␈α∩written␈α⊃so␈α∩as␈α⊃to␈α∩sweep␈α⊃under␈α∩the␈α⊃rug␈α∩the␈α⊃limitations␈α∩of␈α⊃the␈α∩methods.␈α⊃ For
␈↓ α∧␈↓example,␈αthis␈αpaper␈αignores␈αevents␈αextended␈αin␈αtime␈αand␈αthe␈αnotion␈αthat␈αone␈αevent␈αoccurs␈α␈↓↓during␈↓
␈↓ α∧␈↓another.  We have the sentences

␈↓ α∧␈↓␈↓ αT1. ␈↓↓John has visited Paris twice␈↓.

␈↓ α∧␈↓␈↓ αT2. ␈↓↓John has been visiting Paris for three weeks␈↓.

␈↓ α∧␈↓␈↓ αT3. ␈↓↓John was going to school when he fell off his bike␈↓.

␈↓ α∧␈↓␈↓ αT4. ␈↓↓John came every other week␈↓.

␈↓ α∧␈↓Here are some other comments:

␈↓ α∧␈↓1. Fig. 2 shows no output from the user or input to memory.

␈↓ α∧␈↓2.␈α∞The␈α∞statement␈α∞on␈α∞p.␈α
11␈α∞that␈α∞"Typically,␈α∞the␈α∞time␈α∞of␈α
a␈α∞special␈α∞reference␈α∞event␈α∞is␈α∞known␈α
quite
␈↓ α∧␈↓precisely" seems dubious optimism about the applicability of the program.

␈↓ α∧␈↓3.␈α∞The␈α
time␈α∞travel␈α
example␈α∞seems␈α
a␈α∞strange␈α
way␈α∞to␈α
go␈α∞given␈α
the␈α∞inability␈α
of␈α∞the␈α
system␈α∞to␈α
deal
␈↓ α∧␈↓with the more important notion of duration.

␈↓ α∧␈↓␈↓ αTOn␈α⊂the␈α⊂whole,␈α⊂I␈α⊂think␈α⊂the␈α⊂paper␈α⊃should␈α⊂be␈α⊂published␈α⊂if␈α⊂the␈α⊂authors␈α⊂discuss␈α⊃the␈α⊂issues
␈↓ α∧␈↓mentioned above.









␈↓ α∧␈↓␈↓ ε|1␈↓ ∧