0-junction : Kirchoff's currents law
1-junction : Kirchoff's voltage law
0-junction : Geometric compatibility for a situation involving a single force and several velocities which algebraically sum to zero
1-junction : Dynamic equilibrium of forces associated with a single velocity (Newton's law when an inertia element is involved).
0-junction : Conservation of volume flow rate
1-junction : requirement that the sum of pressure drops around a circuit involving