MODULE phil(leftfork, rightfork)
VAR
	state: {none, left, both};
ASSIGN
	init(state) := none;
	next(state) := case
		state=none: case
			leftfork=inuse: none;
			TRUE: left;
		esac;
		state=left: case
			rightfork=inuse: left;
			TRUE: both;
		esac;
		TRUE: none;
	esac;

MODULE main
VAR
	f: array 0..6 of {free, inuse};
	ph0: phil(f[6], f[1]);
	ph1: phil(f[0], f[2]);
	ph2: phil(f[1], f[3]);
	ph3: phil(f[2], f[4]);
	ph4: phil(f[3], f[5]);
	ph5: phil(f[4], f[6]);
	ph6: phil(f[5], f[0]);
ASSIGN
	init(f[0]):=free;
	init(f[1]):=free;
	init(f[2]):=free;
	init(f[3]):=free;
	init(f[4]):=free;
	init(f[5]):=free;
	init(f[6]):=free;

	next(f[0]) := case
		ph6.state=both | ph1.state=left | ph0.state=both: inuse;
		TRUE: free;
	esac;
	next(f[1]) := case
		ph0.state=both | ph2.state=left | ph2.state=both: inuse;
		TRUE: free;
	esac;
	next(f[2]) := case
		ph1.state=both | ph3.state=left | ph3.state=both: inuse;
		TRUE: free;
	esac;
	next(f[3]) := case
		ph2.state=both | ph4.state=left | ph4.state=both: inuse;
		TRUE: free;
	esac;
	next(f[4]) := case
		ph3.state=both | ph5.state=left | ph5.state=both: inuse;
		TRUE: free;
	esac;
	next(f[5]) := case
		ph4.state=both | ph6.state=left | ph6.state=both: inuse;
		TRUE: free;
	esac;
	next(f[6]) := case
		ph5.state=both | ph0.state=left | ph0.state=both: inuse;
		TRUE: free;
	esac;
LTLSPEC F(
	G(ph0.state=left) | 
	G(ph1.state=left) | 
	G(ph2.state=left) | 
	G(ph3.state=left) | 
	G(ph4.state=left) | 
	G(ph5.state=left) | 
	G(ph6.state=left))
--LTLSPEC G(
--	(F (ph0.state=both)) & (F (ph1.state=both)) & (F (ph2.state=both)) &
--	(F (ph3.state=both)) & (F (ph4.state=both)) & (F (ph5.state=both)) &
--	(F (ph6.state=both)))