Hi, I'm in the masters year of a theoretical physics course which begins this September. I'm reading the classical mechanics notes ahead of time, and I came across the idea of holonomic and non-holonomic constraints. I understand that in the case of a holonomic system, you can use the constraints to reduce the number of variables needed to describe that system, and thus find generalised co ordinates. I'm a bit unclear on what constitutes a holonomic constraint though. Any information I've found online seems to only tell me two things: That a holonomic constraint can be represented in the form f(q, t) = 0, (With q being generalised co-ordinates) and That a holonomic constraint is an equality, whereas a non-holonomic constraint is an inequality. These seem a bit vague though, and any advice or tips would be very helpful! Thanks!