Polynomial-time sparse trinomial generation

The output length and three position tests are unary arithmetic functions. The bitwise closure assembles their flags into the coefficient list.

theorem Complexity.BitPolynomial.Internal.trinomialEval_mem_FP : trinomialEval ∈ FP

theorem Complexity.BitPolynomial.Internal.trinomialBits_mem_FP {d : List Bool → ℕ} (hd : UnaryFn d) : (fun (z : List Bool) => trinomialBits (d z)) ∈ FP

theorem Complexity.BitPolynomial.Internal.roundedTrinomialEval_mem_FP : roundedTrinomialEval ∈ FP