Sum eq half Sum
ArkLib.Lattices.CyclotomicModulus.sum_eq_halfSum
Plain-language statement
Splitting the degree-2^α sum into low/high halves and factoring ζ^{2^{α-1}} = s collects the coefficient of ζ^j as a_j + s·a_{2^{α-1}+j}.
Source project: ArkLib
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