Dr. Gavin Wood is the founder of Polkadot. He is a computer scientist and holds a PhD in human-computer interfacing. Charles Hoskinson is the founder of Cardano. He is a mathematician and did not complete a PhD. Charles and Gavin also co-founded with Vitalik Buterin and 5 others in 2013.   Charles seems to spend a lot more time engaging with the Cardano community than Gavin does engage with the Polkadot community. Gavin and Charles have radically different approaches to building their respective projects. Polkadot tests feature using Kusama, and Cardano’s features are peer-reviewed by academics prior to implementation.