Vol.50, No.1(2026)※ PDF is limited to exchange partner.  Author Title Page Yuta Sasahara Four-dimensional isoparametric hypersurfaces of index 2 in the pseudo-Riemannian space forms 1 Noriko Hirata-Kohno, Ryuji Muroi and Yusuke Washio Approximation measures for shifted logarithms of algebraic numbers via effective Poincaré-Perron 37 Makoto Nagata and Yoshinori Takei A Congruential Recurrence Characterizes the Inverses of SÓS Permutations 53 Shigeaki Yokota Geometry of Geometric Data Set I 87 Eiji Miyanohara Remarks on algebraically independence of the certain two infinite products 121 Alejandro Rios Herrejón and Ángel Tamariz Mascarúa On Calibers for C_p(x) 133