2018/11/29 by Xiang‐dong Hou, Hou, Xiang-dong, Ziran Tu +3 · 1 citation
Computer Science · Mathematics · #11T06 #11T55 #14H05 #Advanced Algebra and Geometry #Algebraic Geometry and Number Theory #Coding theory and cryptography #FOS: Mathematics #Number Theory (math.NT)
paper · pdf · doi:10.48550/arxiv.1811.11949
openalex publication_date 2018/11/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Let f(X)=X(1+aXq(q-1)+bX2(q-1))∈\Bbb Fq2[X], where a,b∈\Bbb Fq2^*. In a series of recent papers by several authors, sufficient conditions on a and b were found for f to be a permutation polynomial (PP) of \Bbb Fq2 and, in characteristic 2, the sufficient conditions were shown to be necessary. In the present paper, we confirm that in characteristic 3, the sufficient conditions are also necessary. More precisely, we show that when char \Bbb Fq=3, f is a PP of \Bbb Fq2 if and only if (ab)q=a(bq+1-aq+1) and 1-(b/a)q+1 is a square in \Bbb Fq^*.