Help understanding Polygon architecture? Any technical experts?


I’m a blockchain analyst from Brazil and I have been studying Polygon for the last few days, but there are some technical details I’m having a hard time to grasp, which I’m hoping this community could be able to help me clarify.

I understand I can send/withdraw tokens from ETH->MATIC commit-chain using two bridges, being PoS Bridge and Plasma Bridge, and also I understand the difference between both bridges, in terms of methods and time estimates.

What I don’t understand so far, is that if assets bridged from both bridges end up on the same account on the same state of the same ledger, or if internally Polygon mantains two separate chains for PoS bridged assets and Plasma Bridged assets.

It seems odd to me that it would be the same chain/ledger, as one achieves consensus thru a set of L2 validators, and the other one relies on a single operator that has the abilty to change the blockchain state at his own will.

How could such different mechanisms coexist and produce the same blocks? And how could they deal with attempts to withdraw the same funds from both bridges at the same time, regarding conciliation of information, or fraud-proof processing in case of plasma?

For instance, if a fraud-proof is sucessfully submitted, and the whole chain is reverted to a previous checkpoint, how can assets that where withdrawn via PoS bridge be reverted as well?

And if they happen to be separate ledgers internally, how is it that their fragmented liquidity can be consolidated for the end user experience withouth extra security risks?

If there is any technical document I’m so far unaware of, that clarify these questions, I would be very grateful to anyone that can direct me to them.