If it is the relationship to the Mach number you're looking for, then there is a simple way to remember, here we go:
Chicken Tikka Massala
C for Calibrated (most aircraft today display CAS as IAS)
T for True airspeed (TAS)
M for Mach
At sea level, in ISA, all 3 should nearly be in the same spot, as well as Ground Speed if there is no wind.
As you gain altitude, C is less than T, and T is less than M.
3 possible scenarios (scenarii for the purists):
Constant CAS = TAS & Mach will increase with altitude
Constant TAS = CAS decreases and Mach increases with altitude
Constant Mach = CAS & TAS decrease with altitude
But I am probably off-topic, unless your question was about the Mach, and not the LSS.
Flex