Partial Derivatives in Arithmetic Complexity and Beyond Xi Chen Columbia University USA xichen @cs. columbia.edu Neeraj Kayal Microsoft Research India neera ka <§ microsoft, com Avi Wigderson Institute for Advanced Study USA avi@ias. edu n«w the essence of knowledge Boston - Delft Contents 1 Introduction 1 1.1 Motivation 1 1.2 Arithmetic Circuits 4 1.3 Formal Derivatives and Their Properties 9 Part I: Structure 2 Symmetries of 13 a Polynomial 17 2.1 Proof of Lemma 2.1 21 2.2 Proof of Lemma 2.4 25 3 Algebraic Independence 27 4 Polynomials 33 5 Bezout's Theorem with High Arithmetic Complexity 5.1 A 5.2 Proof of Theorem 5.2 5.3 Proof of Lemma 5.3 5.4 Bezout's Theorem 37 Property of Isolated Roots over 38 39 42 Finite Fields and ix Rings 43 5.5 A Brief Introduction to the 5.6 6 44 Sketch of Proof of Theorem 5.6 46 Algebraic Extractors Jacobian 6.1 p-adic Numbers, Norm, and Metric and the Conjecture The Jacobian 7 The "Joints 8 The 49 50 Conjecture Conjecture" Resolved 53 Stepanov Method 55 8.1 Weil's Theorem on Rational Points 8.2 A 8.3 Formal Proof of Weil's Theorem 66 8.4 The Heath-Brown and Mit'kin Estimates 70 on Curves High-level Description of the Stepanov Method 56 62 Part II: Lower Bounds 73 9 75 General Arithmetic Circuits 10 Sums of Powers of Linear Forms 10.1 Arithmetic Circuits with Addition and 10.2 11 85 Powering Gates Depth-2 Symmetric Arithmetic Circuits Depth-3 Arithmetic Circuits 88 88 91 12 Arithmetic Formulae 95 12.1 Cover Sets and Measure Functions 97 12.2 A 98 Constant-depth Lower Bound 13 Projections Part III: 14 of Determinant to Permanent Algorithms 109 Identity Testing 111 14.1 POLYDEP and its Connection to 14.2 Basic 14.3 The Identity Testing Properties of POLYDEP Algorithm 15 Absolute 103 112 113 114 Irreducibility Testing 119 15.1 Notation 120 15.2 122 16 Consequences Polynomial Equivalence Testing 16.1 Algorithm 16.2 Equivalence to a Sum of Powers 16.3 Equivalence to for Minimizing the Number of Variables Acknowledgments References an Elementary Symmetric Polynomial 125 128 130 132 139