If heir value less than 1 then the network is unconditionally unstable on the frequencies concerned. For mu1 and mu2, the higher the value the more stable the network is.
If the value of any of these 3 factors is more than 1 then the two port network is conditionally stable.
It is well documented on the microwave101 website and is rno rocket science to calculate this. These are stability indicators that can be easily calculated based on the 4 S parameters.
(according to me) is to code as a first priority in sinsimsmith, the mu1, mu2 and K Rolet factors.
