(part-type 'rc
	   '()
	   '()
	   '((any-model
	      (n1 n2 gnd)
	      ((v voltage-source n1 gnd)
	       (r resistor n1 n2)
	       (c capacitor n2 gnd))
	      ()
	      ((gnd-potential
		(= (>> potential gnd) 0)))))
	   '())

(define n
  (create-circuit 'N 'rc '(bias incremental)))
			
(assume-value n '(voltage v bias) 6)

(assume-value n '(resistance r) 2)

(propagate (constraint-network n))

(the-value n '(voltage c bias))
; ((voltage c bias) = 6)
;   (set by (-rhs:kvl c bias))
;     (because ((potential n2 bias) (potential gnd bias)))

(the-value n '(voltage c incremental))
; ((voltage c incremental) = 0)
;   (set by (v:rhs:shorted c incremental))
;     (because ())

(the-value n '(voltage r incremental))
; ((voltage r incremental) is not assigned)

(assume-value n '(current t1 c incremental) .001)

(the-value n '(voltage r incremental))
; ((voltage r incremental) is not assigned)

(propagate (constraint-network n))

(the-value n '(voltage r incremental))
; ((voltage r incremental) = .002)
;   (set by (*rhs:ohm r incremental))
;     (because ((resistance r) (current t1 r incremental)))