Konstantin Ziegler

  1. Composition collisions and projective polynomials.

    Authors: Joachim von zur Gathen, Konstantin Ziegler, Mark Giesbrecht
    Subjects: Commutative Algebra
    Abstract

    The functional decomposition of polynomials has been a topic of great
    interest and importance in pure and computer algebra and their applications.
    The structure of compositions of (suitably normalized) polynomials f=g(h) over
    finite fields is well understood in many cases, but quite poorly when the
    degrees of both components are divisible by the characteristic p. This work
    investigates the decomposition of polynomials whose degree is a power of p.

  2. Counting reducible, powerful, and relatively irreducible multivariate polynomials over finite fields.

    Authors: Joachim von zur Gathen, Alfredo Viola, Konstantin Ziegler
    Subjects: Commutative Algebra
    Abstract

    We present counting methods for some special classes of multivariate
    polynomials over a finite field, namely the reducible ones, the s-powerful ones
    (divisible by the s-th power of a nonconstant polynomial), and the relatively
    irreducible ones (irreducible but reducible over an extension field). One
    approach employs generating functions, another one a combinatorial method. They
    yield approximations with relative errors that essentially decrease
    exponentially in the input size.

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