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SUMMARY:Quantifier Heuristics in HOL4 - Thomas Tuerk (University of Cambri
 dge)
DTSTART:20110201T131500Z
DTEND:20110201T141500Z
UID:TALK29434@talks.cam.ac.uk
CONTACT:William Denman
DESCRIPTION:Automatically guessing instantiations for quantifiers is often
  very useful. Using the Unwind library\, HOL4's simplifier can simplify te
 rms like  \n∀x y. P (x\,y) ∧ (x = 2) ⇒ Q x to\n∀y. P (2\,y) ⇒ Q 
 2. However\, even slightly more complicated terms like ∀x. (∃y. P (x\,
 y) ∧ (x = 2)) ⇒ Q x\ncannot be simplified. \n\nIn this talk\, I presen
 t the quantifier heuristics library. In contrast to the Unwind library\, t
 he quantifier heuristics library does not use a fixed set of term patterns
 . Instead\, an extensible set of heuristics produce guesses for subterms. 
 These guesses are then combined for larger terms.\n\nThe quantifier heuris
 tics library can simplify more complicated terms than the Unwind library. 
 Moreover\, it is easily extensible by adding new heuristics. An interestin
 g feature is partial instantiations\, i.e. instantiations that introduce n
 ew quantifiers. This allows to simplify for examples the term ∀x. IS_SOM
 E x ⇒ P x to ∀x_x. P (SOME x_x).\n\nI will try to present the library 
 without referring to too many HOL4 details. However\, it's a talk about th
 e concrete implementation in HOL4. The theoretical ideas behind the librar
 y are very simple.
LOCATION:Computer Laboratory\, William Gates Building\, Room SS03
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