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sav07_lecture_3_skeleton [2007/03/21 09:51] vkuncak |
sav07_lecture_3_skeleton [2007/03/21 10:15] vkuncak |
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Proof: small model theorem. | Proof: small model theorem. | ||
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where $A \in {\cal Z}^{m,n}$ and $x \in {\cal Z}^n$. | where $A \in {\cal Z}^{m,n}$ and $x \in {\cal Z}^n$. | ||
- | Then use small model theorem for integer linear programming (ILP). | + | Then solve integer linear programming (ILP) problem |
+ | * [[wk>Integer Linear Programming]] | ||
+ | * online book chapter on ILP | ||
+ | * [[http://www.gnu.org/software/glpk/|GLPK]] tool | ||
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+ | We can prove small model theorem for ILP - gives bound on search. | ||
- | Short proof by {{papadimitriou81complexityintegerprogramming.pdf|Papadimitriou}}. | + | Short proof by {{papadimitriou81complexityintegerprogramming.pdf|Papadimitriou}}: |
+ | * solution of Ax=b (A regular) has as components rationals of form p/q with bounded p,q | ||
+ | * duality of linear programming | ||
+ | * obtains bound $M = n(ma)^{2m+1}$. | ||
Note: if small model theorem applies to conjunctions, it also applies to arbitrary QFPA formulas. Moreover, one can improve these bounds. One tool based on these ideas is [[http://www.cs.cmu.edu/~uclid/|UCLID]]. | Note: if small model theorem applies to conjunctions, it also applies to arbitrary QFPA formulas. Moreover, one can improve these bounds. One tool based on these ideas is [[http://www.cs.cmu.edu/~uclid/|UCLID]]. |