;;;;
;;;;"A Qualitative Dynamical Modelling Approach
;;;; to Capital Accumualtion in Atomistic Open-Access Fisheries"
;;;;
;;;; Journal of Economic Dynamics and Control
;;;;
;;;; The toymodel (section 2)
;;;;
;;;; Eisenack et al., V. 6.7.2004
;;;;
;;;; Start simulation with 
;;;;   ./cq -I toymodel.run
;;;;
;;;; Result: state transition graph with 10 states
;;;; (after all standard filtering procedures).
;;;; One initial state is identical to another intermediate one.
;;;; View with: stg <CR> x <CR>  h <CR><CR>
;;;; 

;;; Begin definition of model

(quantity-spaces
 (x (0 xmsy Q xmax) "x")
 (h (0 MSY hmax)    "h")
 (R (0 Rmsy Rmax)   "R")
 (dx (minf 0 inf)   "dx")) ; dx \in (-\infty, 0) or \in (0, \infty) or =0

(constraints
 ((d//dt x dx))
 ((add dx h R) (0 0 0) (0 MSY Rmsy))
 ((U- x R) (xmsy Rmsy) (0 0) (Q 0))
 ((M+ x h) (0 0)); (inf inf))

 ;; Exclusion of marginal cases (e.g. case (iii) in section 2)
 ((cornot x dx) (xmsy 0)) 
 ((cornot h dx) (MSY 0)) 
)

;;; technical directives

(unreachable-values (x xmax) (h hmax) (R Rmax))

(weak-cycles)

(with-envisionment)

;;; initial state of simulation

(make-initial-state 
 (x (nil nil)))