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Application of machine learning to RCF decision procedures. Zongyan Huang. What is MetiTarski. Automatic theorem prover Prove universally quantified inequalities involving special functions (ln, exp, sin, etc.,.) e.g. Prove within a second!. Why reasoning about special functions.
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Application of machine learning to RCF decision procedures Zongyan Huang
What is MetiTarski • Automatic theorem prover • Prove universally quantified inequalities involving special functions (ln, exp, sin, etc.,.) e.g. Prove within a second!
Why reasoning about special functions • Wide ranges of engineering applications • Mechanical systems • Electrical circuits • Chemical process control • Embedded computation systems • Hybrid systems are dynamic system which exhibits both continuous and discrete dynamic behavior • Properties are expressed by formula involving special functions
How MetiTarski works • Combines a resolution theorem prover (Metis) with RCF decision procedures • The theory of RCF concerns boolean combinations of polynomial equations and inequalities over the real numbers • Eliminate special functions (upper and lower bounds) • Transform parts of the problem into polynomial inequalities • Apply a RCF decision procedure
RCF decision procedures • Proof search generates a series of RCF subproblems • Simplify clauses by deleting literals that are inconsistent with other algebraic facts • RCF Strategies used • QEPCAD • Mathematica • Z3 • No single RCF decision procedure always gives the fastest runtime • Use machine learning to find the “best” RCF strategy
Machine Learning • Statistical methods to infer information from training examples • Information applied to new problems • The Support Vector Machine (Joachims’ SVMLight) • SVM learn: generate model • SVM classify: predict the class label and output the margin values
Methodology • Identify features of the problems • Select the best kernel function and parameter values for SVM-Light base on F1maximization • Combine the models for decision procedures • Compare the margin values. The classifier with most positive (or least negative) margin was selected.
Results • The experiment was done on 825 MetiTarski problems • The total number of problems proved out of 194 testing problems was used to measure the efficacy • Machine learned selection yields better results than any individual fixed decision procedure
Future work • Extend to the heuristic selection within decision procedures • Extend the range of features used and apply feature selection • Provide feedback for development of RCF decision procedures