Is Radix decentralized?

Yes, Radix is decentralized.

The Radix Protocol is defined to automatically choose the validators that verify transactions on the Radix Public Network. This is based upon the amount of stake delegated to validators by the decentralized community of XRD token holders. 

The Radix Foundation or any other entities will never have the ability to apply permissions (see here for more detail on this topic). 

The Radix Foundation has policies (linked below) concerning running its own validators and delegating its own stake.

Further reading:

• What do distributed and decentralized mean?
• How are validators on Radix selected?
• What is the Radix Foundation’s policy on staking & node-running?
• Will Radix operate validator nodes?
• Will Radix stake its own XRD holdings? To which validators?
• Will Radix receive incentive rewards from staking and validator node-running?
• Will Radix-operated validator nodes accept delegated stake from the community?