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Quasi-linear MBB evaluation of known sparse polynomials at large modulus and degree

Develop a quasi-linear time algorithm for modular black box (MBB) evaluation of a known sparse integer polynomial when both the polynomial’s degree and the evaluation modulus are large; specifically, compute f(a) mod m with total bit complexity quasi-linear in the bit-length of f and log m under these conditions.

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Background

The paper relies on a multi-point modular derivative black box (MDBB) model to enable efficient subroutines. When attempting to update an unknown polynomial black box with an explicitly computed partial result, the authors identify a limitation of the traditional MBB model: efficient evaluation of a known sparse polynomial at large modulus and degree is not known to be achievable in quasi-linear time.

This gap motivates the MDBB approach and is explicitly stated as an unresolved capability in the MBB framework.

References

This update creates a problem for the MBB model, as we do not know any quasi-linear time algorithm for MBB evaluation of a known sparse polynomial where the degree and evaluation modulus may both be large.

Fast interpolation and multiplication of unbalanced polynomials (2402.10139 - Giorgi et al., 15 Feb 2024) in Section 2.3, Black Boxes: MBBs and MDBBs