In mathematics, the Meyer signature cocycle, introduced by Meyer (1973). is an integer-valued 2-cocyle on a symplectic group that describes the signature of a fiber bundle whose base and fiber are both Riemann surfaces.
References
Atiyah, Michael Francis (1969), "The signature of fibre-bundles", Global Analysis (Papers in Honor of K. Kodaira), Tokyo: Univ. Tokyo Press, pp. 73–84, MR0254864