Rational functions of degree four that permute the projective line over a finite field
Xiang‐dong Hou · Communications in Algebra · 2021
Recently, rational functions of degree three that permute the projective line P1(Fq) over a finite field Fq were determined by Ferraguti and Micheli. In the present paper, using a different method, we determine all rational functions of degree four that permute P1(Fq).