checked exclhi rings:
{ a, b, c }
checked excllo rings:
	0	a : 1
	0	b : 0
	0	c : 0
ignoring... 
WARNING: detected exclusion violation, but because the simulation is
continuing (current policy), further exclusion checking is automatically
disabled because the checking structures would be incoherent otherwise.
	0	b : 1
	0	b : 0
