¥Threshold: some particles feel forces
¥All N forced* particles must have balanced forces.
d N constraints on contact forces in d dimensions
Requires** at least d N contacts.
¥Adiabatic jamming adds contacts one by one: stops when forces balance
¥É expect marginally jammed state to have just d N contacts: isostatic
i.e. minimal number of contacts to fix particle positions.
¥Observed in simulation
Marginally jammed particles are isostatic
* Unforced particles (floaters) appear to play a minor role
(number of contact constraints = number of degrees of freedom)