In Riemann geometry and algebraic topology, both parts of mathematics, the Riemann-Hurwitz formula, named after Bernhard Riemann and Adolf Hurwitz, describes the relationship of the Euler characteristics of two surfaces when one of these surfaces is a branched cover of the other. In this case, the proposition relates to the branching theory and algebraic topology. It is a prototyping result for many others and is often used in the theory of the Riemann surfaces (here the proposition originates) and the algebraic curves.
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