Abstract
A symmetric Riemann surface is a pair (X, σ) where X is a Riemann surface and σ is an anticonformal involution. We denote by Aut(X, σ) the subgroup of Aut(X) defined by the automorphisms commuting with σ. There is a natural isomorphism between Aut(X, σ) and Aut(X/σ). In this article we shall show that this isomorphism does not stand if X is a Riemann surface with nodes.
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