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The paper suggests a preconditioning type method for fast solving of elliptic equations with oscillating quasiperiodic coefficients
All the information related to complicated coefficients of the original differential problem is encompasses in the linear functional, which forms the right hand side of the auxiliary problem. Therefore, explicit inversion of the original operator associated with oscillating coefficients is avoided. The only operation used instead is multiplication of the operator by a vector (vector function), which can be efficiently performed due to the low-rank QTT tensor operations with the rank parameter controlled by the given precision
We deduce two--sided a posteriori error estimates that do not use