BasisGen: automatic generation of operator bases Criado, Juan Carlos BasisGen is a Python package for the automatic generation of bases of operators in effective field theories. It accepts any semisimple symmetry group and fields in any of its finite dimensional irreducible representations. It takes into account integration by parts redundancy and, optionally, the use of equations of motion. The implementation is based on well-known methods to generate and decompose representations using roots and weights, which allow for fast calculations, even with large numbers of fields and high-dimensional operators. BasisGen can also be used to do some representation-theoretic operations, such as finding the weight system of an irreducible representation from its highest weight or decomposing a tensor product of representations. 2020-04-23T11:50:24Z 2020-04-23T11:50:24Z 2019-03-21 journal article Criado, J.C. BasisGen: automatic generation of operator bases. Eur. Phys. J. C 79, 256 (2019). [https://doi.org/10.1140/epjc/s10052-019-6769-5] http://hdl.handle.net/10481/61530 10.1140/epjc/s10052-019-6769-5 eng http://creativecommons.org/licenses/by/3.0/es/ open access Atribución 3.0 España Springer Nature