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Abstract

We provide upper bounds for the size of subsets of finite fields lacking the polynomial progression $$ x, x+y, \ldots , x+(m-1)y, x+y^m, \ldots , x+y^{m+k-1}.$$ These are the first known upper bounds in the polynomial Szemerédi theorem for the case when polynomials are neither linearly independent nor homogeneous of the same degree. We moreover improve known bounds for subsets of finite fields lacking arithmetic progressions with a difference coming from the set of $k$th power residues, i.e. configurations of the form $$ x, x+y^k, \ldots , x+(m-1)y^k.$$ Both results follow from an estimate of the number of such progressions in an arbitrary subset of a finite field.