ConcurrentCes Definition

# Are the inputed circles concurrent?
# If the inputed (equations of the) circles are C1=0, C2=0, C3=0, ...
# it solves the system of linear equations
# {C1-C2=0, C1-C3=0, ...} and if there is a solution [x,y],
# plugs it into C1, C2, C3, ... to check whether this point
# lies on all inputed circles

ConcurrentCes:=proc() local P,i:

P:=subs(solve({seq(args[1]-args[i],i=2..nargs)},{x,y}),[x,y]):

for i from 1 to nargs do
  if   not PtLiesOnCurve (P,args[i]) then RETURN(false):   fi:
od:

true:

end: