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Paper "How to Meet Ternary LWE Keys": Why can Odlyzko's hash function not be used to construct the mitm lists recursively?

cn flag

In Alexander May's Paper "How to Meet Ternary LWE Keys", Alexander May writes the following about combining representation techniques with Odlyzko's locality sensitive hash function (Page 12):

Intuitively, in a subset sum-type approach of the representation technique as in [HJ10], one would try to construct two lists $L_1$, $L_2$ with entries $(s_1, \ell(As_1)), (s_2, \ell(b − As_2))$ recursively such that on expectation $L_1 \times L_2$ contains a single representation. However, the non-linearity of Odlyzko’s hash function hinders such a direct recursive application of the representation technique.

I am trying to get a more solid understanding on why that is. If I understand correctly, a recursive application would try to split up the $s_1$ and $s_2$ even further (using again the representation technique) into another $s_1 = s^{(2)}_1 + s^{(2)}_2$ and then filter out representations such that, in expectation, one correct representation of $s_1$ and $s_2$ remains. It is however not so clear to me how exactly one would go about such a recursive construction and why it is prevented by the non-linearity of the locality sensitive hash function?

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ng flag
Skimming the paper, one obstacle to the recursive construction is that for things that hash into the set of "border values", they get a label that is a subset, not a single value. Managing the size of this subset under the recursion could quickly become annoying (and have negative efficiency impacts). I don't know if this is the only issue (or if it is an issue at all frankly), but May's final construction seems to no longer have this property, so it seems plausible it is what he is referring to.
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