Is Bittensor built on Polkadot?

Could you please enlighten me on whether Bittensor is indeed constructed upon the foundation of Polkadot? I'm keen to understand the technological underpinnings of this project and how it interfaces with Polkadot, if indeed it does. Could you elaborate on the potential benefits or advantages of such an architecture, and also shed light on any challenges or limitations that might arise from this choice? Additionally, I'm interested in knowing if there are any specific features or functionalities of Bittensor that are enabled or enhanced by being built on Polkadot. Thank you for your insights.