DecreaseAtRate is a binary q-operator for expressing negative influencingcomponents of a quantity-term.
Eg: (IncreaseAtRate (Device-9 heatContent) (Process-14 heatGenerationRate)) and
(DecreaseAtRate (Device-9 heatContent) (Process-26 heatRemovalRate))
together
states that the heat content of Device-9 is changing (assuming no other influences)
at a rate equal to the difference between Process-14's rate and
Process-26's rate.
DecreaseByAmt expressions are constraints, and do not evaluate to values.