What is the validator fee in radix?

Could you elaborate on the validator fee structure in Radix? Specifically, I'm curious about how it's calculated, what factors influence its determination, and how often these fees are adjusted. Understanding the validator fee is crucial for those interested in participating in Radix's staking or validation process, as it directly impacts their potential rewards and incentives. Additionally, is there a minimum or maximum fee, and how does this compare to other cryptocurrency networks? Your insights into this aspect of Radix's economics would be greatly appreciated.