Is Polkadot centralized or decentralized?

I've been hearing a lot about Polkadot recently, and I'm curious about its structure. Could you please clarify whether Polkadot is centralized or decentralized? I've read conflicting opinions on this matter, and I'm trying to get a better understanding. As a professional in the field of cryptocurrency and finance, I'm sure you have a deep understanding of this topic. Could you elaborate on the key characteristics of Polkadot's architecture and explain whether it leans more towards centralization or decentralization? I'm really interested in learning more about this emerging blockchain project.