MAYBE
Time: 0.012

Problem:
 Equations:
  
 TRS:
  eqC(0(),0()) -> true()
  eqC(0(),s(x)) -> false()
  eqC(s(x),0()) -> false()
  eqC(s(x),s(y)) -> eqC(x,y)
  or(true(),y) -> true()
  or(false(),y) -> y
  union(empty(),h) -> h
  union(edge(x,y,i),h) -> edge(x,y,union(i,h))
  reach(x,y,empty(),h) -> false()
  reach(x,y,edge(u,v,i),h) -> if_reach_1(eqC(x,u),x,y,edge(u,v,i),h)
  if_reach_1(true(),x,y,edge(u,v,i),h) -> if_reach_2(eqC(y,v),x,y,edge(u,v,i),h)
  if_reach_1(false(),x,y,edge(u,v,i),h) -> reach(x,y,i,edge(u,v,h))
  if_reach_2(true(),x,y,edge(u,v,i),h) -> true()
  if_reach_2(false(),x,y,edge(u,v,i),h) -> or(reach(x,y,i,h),reach(v,y,union(i,h),empty()))

Proof:
 Open