Omri Ben-Eliezer Optimal testing of local properties via spherical queries Abstract: A property of d-dimensional arrays is considered k-local if the set of k * ... * k consecutive sub-arrays of a given array completely determines whether the array satisfies the property. We present a simple yet canonical and powerful alphabet-independent non-adaptive one-sided error approach to test any k-local property over any finite (and not necessarily bounded-size) alphabet, based on querying sphere-like structures of varying sizes. The query complexity turns out to be optimal for a very wide range of parameters, and for the case d=1 it even matches the two-sided adaptive query complexity of monotonicity.