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arkworks-rs / marlin

A Rust library for the Marlin preprocessing zkSNARK
Apache License 2.0
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A question in Marlin paper in section 5.3.2 #81

Closed wang12d closed 2 years ago

wang12d commented 3 years ago

Hello arkworks-rs, thanks for your the greater work Marlin. While reading the paper I encountered a question.

In page 28, section 5.3.2, it says:

However, in the same page equation (6) it says sums to on H. Therefor, according the univariate sumcheck for subgroups protocol introduced in section 5.1, should be written as:

if is not zero. Is my understanding about wrong or something I have missed? Any help is appreciated, thanks.

weikengchen commented 3 years ago

I feel it is a typo, but @Pratyush can confirm.

On Figure 5 on page 32, we can see that \sigma_1 is back. And \sigma_1 is the sum of the mask polynomial s(\kappa) on domain H, which is unlikely to be zero.

weikengchen commented 2 years ago

Marked as closed.

Pratyush commented 2 years ago

we can sample the mask polynomial to indeed sum to zero on H, so in this case the two would be equivalent.