> ## Documentation Index
> Fetch the complete documentation index at: https://docs.starknet.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Introduction

> This section presents the implementation of the polynomial commitment scheme in S-two, which is built on top of the FRI protocol described previously. Polynomial commitments are a core cryptographic primitive that enable a prover to commit to a polynomial and later reveal evaluations at specific points.

This section is organized as follows:

* [**Overview**](/learn/S-two-book/how-it-works/pcs/overview): Describes the polynomial commitment scheme of S-two.
* [**PCS Prover**](/learn/S-two-book/how-it-works/pcs/prover): Details the implementation of the prover for the polynomial commitment scheme, including commitment and opening protocol.
* [**PCS Verifier**](/learn/S-two-book/how-it-works/pcs/verifier): Describes the verifier implementation for checking commitments and evaluation proofs.