Theorem 1.1 of Ran Raz's paper is a non-constructive upper bound on the soundness error of parallel repetitions of a 2-prover minimally minimally interactive proof system with perfect completeness.As far as I can see, despite the second sentence of that paper's abstract suggesting otherwise, that paper does not give a constructive upper bound on the relevant quantities.Is there a known constructive upper bound on the soundness error of parallel repetitions of a 2-prover minimally minimally interactive proof system with perfect completeness?
Is there a constructive parallel repetition theorem for nice MIP protocols?
interactive proofs
In his simplified proof of the parallel repetition theorem, Holenstein gives the following explicit bound on the value of the $n$-fold parallel repetition of a game with value $v$:$$\left(1-\frac{(1-v)^3}{6000}\right)^{n/\log(|\Sigma_1|\cdot |\Sigma_2|)},$$where $\Sigma_1, \Sigma_2$ are the alphabets of the two players. It's not clear to me that Raz's bound is not constructive in your sense; I am wondering what step in his proof you think is not computable. He does not make his bound fully explicit, but I thought this was done more for exposition. 