BULLETIN MATHEMATIQUE DE LA SOCIETE DES SCIENCES MATHEMATIQUES DE ROUMANIE, cilt.68, sa.4, ss.429-439, 2025 (SCI-Expanded, Scopus)
We extend a previous result of Kekec and prove that under certain conditions rational combinations with algebraic formal power series coefficients of a U-1-number are U-m-numbers in the field of formal power series over a finite field.