Stable reduction of X0(p4).

R. Coleman and K. McMurdy calculated the stable reduction of X0(p3) (p ≥ 13) on the basis of the rigid geometry in [8]. In the present paper, we determine the stable reduction of X0(p4) for primes p ≥ 13 on the basis of their idea. As irreducible components in the stable reduction of X0(p4), a certain number of copies of the Hermitian curve, with an affine equation ap - a = tp+1, appear. [ABSTRACT FROM AUTHOR]