Computer algebra is increasingly used in research and applied computations. An example is tensor computations or, in a wide sense, simplification of expressions containing indices. In this paper, the method of colored graphs designed for simplifying abstract expressions containing indices is developed for the case when the indices are of different types. An example of such indices are upper and lower indices in tensor expressions. The proposed approach significantly reduces the number of combinations to be considered when the canonical form of the expression is sought; as a result, the computations are drastically accelerated.
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We are grateful to V. A. Ilyin for fruitful discussions and to S.A. Abramov for stimulating this research and the opportunity to make a report in the seminar on computer algebra .
This work was done within the state project no. 115041410196.
Translated by A. Klimontovich
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Shpiz, G.B., Kryukov, A. The Method of Colored Graphs for Simplifying Expressions with Indices. Program Comput Soft 47, 25–28 (2021). https://doi.org/10.1134/S0361768821010102