Term Rewriting System R:
[x, y, h, i, u, v]
eq(0, 0) -> true
eq(0, s(x)) -> false
eq(s(x), 0) -> false
eq(s(x), s(y)) -> eq(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) -> ifreach1(eq(x, u), x, y, edge(u, v, i), h)
ifreach1(true, x, y, edge(u, v, i), h) -> ifreach2(eq(y, v), x, y, edge(u, v, i), h)
ifreach1(false, x, y, edge(u, v, i), h) -> reach(x, y, i, edge(u, v, h))
ifreach2(true, x, y, edge(u, v, i), h) -> true
ifreach2(false, x, y, edge(u, v, i), h) -> or(reach(x, y, i, h), reach(v, y, union(i, h), empty))

Termination of R to be shown. 



   R
     ↳Dependency Pair Analysis



R contains the following Dependency Pairs:

EQ(s(x), s(y)) -> EQ(x, y)
UNION(edge(x, y, i), h) -> UNION(i, h)
REACH(x, y, edge(u, v, i), h) -> IFREACH1(eq(x, u), x, y, edge(u, v, i), h)
REACH(x, y, edge(u, v, i), h) -> EQ(x, u)
IFREACH1(true, x, y, edge(u, v, i), h) -> IFREACH2(eq(y, v), x, y, edge(u, v, i), h)
IFREACH1(true, x, y, edge(u, v, i), h) -> EQ(y, v)
IFREACH1(false, x, y, edge(u, v, i), h) -> REACH(x, y, i, edge(u, v, h))
IFREACH2(false, x, y, edge(u, v, i), h) -> OR(reach(x, y, i, h), reach(v, y, union(i, h), empty))
IFREACH2(false, x, y, edge(u, v, i), h) -> REACH(x, y, i, h)
IFREACH2(false, x, y, edge(u, v, i), h) -> REACH(v, y, union(i, h), empty)
IFREACH2(false, x, y, edge(u, v, i), h) -> UNION(i, h)

Furthermore, R contains three SCCs. 


   R
     ↳DPs
       →DP Problem 1
         ↳Argument Filtering and Ordering
       →DP Problem 2
         ↳AFS
       →DP Problem 3
         ↳Remaining


Dependency Pair:

EQ(s(x), s(y)) -> EQ(x, y)


Rules:


eq(0, 0) -> true
eq(0, s(x)) -> false
eq(s(x), 0) -> false
eq(s(x), s(y)) -> eq(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) -> ifreach1(eq(x, u), x, y, edge(u, v, i), h)
ifreach1(true, x, y, edge(u, v, i), h) -> ifreach2(eq(y, v), x, y, edge(u, v, i), h)
ifreach1(false, x, y, edge(u, v, i), h) -> reach(x, y, i, edge(u, v, h))
ifreach2(true, x, y, edge(u, v, i), h) -> true
ifreach2(false, x, y, edge(u, v, i), h) -> or(reach(x, y, i, h), reach(v, y, union(i, h), empty))





The following dependency pair can be strictly oriented:

EQ(s(x), s(y)) -> EQ(x, y)


There are no usable rules w.r.t. to the AFS that need to be oriented.
Used ordering: Homeomorphic Embedding Order with EMB
resulting in one new DP problem.
Used Argument Filtering System:
EQ(x1, x2) -> EQ(x1, x2)
s(x1) -> s(x1)


   R
     ↳DPs
       →DP Problem 1
         ↳AFS
           →DP Problem 4
             ↳Dependency Graph
       →DP Problem 2
         ↳AFS
       →DP Problem 3
         ↳Remaining


Dependency Pair:


Rules:


eq(0, 0) -> true
eq(0, s(x)) -> false
eq(s(x), 0) -> false
eq(s(x), s(y)) -> eq(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) -> ifreach1(eq(x, u), x, y, edge(u, v, i), h)
ifreach1(true, x, y, edge(u, v, i), h) -> ifreach2(eq(y, v), x, y, edge(u, v, i), h)
ifreach1(false, x, y, edge(u, v, i), h) -> reach(x, y, i, edge(u, v, h))
ifreach2(true, x, y, edge(u, v, i), h) -> true
ifreach2(false, x, y, edge(u, v, i), h) -> or(reach(x, y, i, h), reach(v, y, union(i, h), empty))





Using the Dependency Graph resulted in no new DP problems.


   R
     ↳DPs
       →DP Problem 1
         ↳AFS
       →DP Problem 2
         ↳Argument Filtering and Ordering
       →DP Problem 3
         ↳Remaining


Dependency Pair:

UNION(edge(x, y, i), h) -> UNION(i, h)


Rules:


eq(0, 0) -> true
eq(0, s(x)) -> false
eq(s(x), 0) -> false
eq(s(x), s(y)) -> eq(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) -> ifreach1(eq(x, u), x, y, edge(u, v, i), h)
ifreach1(true, x, y, edge(u, v, i), h) -> ifreach2(eq(y, v), x, y, edge(u, v, i), h)
ifreach1(false, x, y, edge(u, v, i), h) -> reach(x, y, i, edge(u, v, h))
ifreach2(true, x, y, edge(u, v, i), h) -> true
ifreach2(false, x, y, edge(u, v, i), h) -> or(reach(x, y, i, h), reach(v, y, union(i, h), empty))





The following dependency pair can be strictly oriented:

UNION(edge(x, y, i), h) -> UNION(i, h)


There are no usable rules w.r.t. to the AFS that need to be oriented.
Used ordering: Homeomorphic Embedding Order with EMB
resulting in one new DP problem.
Used Argument Filtering System:
UNION(x1, x2) -> UNION(x1, x2)
edge(x1, x2, x3) -> edge(x1, x2, x3)


   R
     ↳DPs
       →DP Problem 1
         ↳AFS
       →DP Problem 2
         ↳AFS
           →DP Problem 5
             ↳Dependency Graph
       →DP Problem 3
         ↳Remaining


Dependency Pair:


Rules:


eq(0, 0) -> true
eq(0, s(x)) -> false
eq(s(x), 0) -> false
eq(s(x), s(y)) -> eq(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) -> ifreach1(eq(x, u), x, y, edge(u, v, i), h)
ifreach1(true, x, y, edge(u, v, i), h) -> ifreach2(eq(y, v), x, y, edge(u, v, i), h)
ifreach1(false, x, y, edge(u, v, i), h) -> reach(x, y, i, edge(u, v, h))
ifreach2(true, x, y, edge(u, v, i), h) -> true
ifreach2(false, x, y, edge(u, v, i), h) -> or(reach(x, y, i, h), reach(v, y, union(i, h), empty))





Using the Dependency Graph resulted in no new DP problems.


   R
     ↳DPs
       →DP Problem 1
         ↳AFS
       →DP Problem 2
         ↳AFS
       →DP Problem 3
         ↳Remaining Obligation(s)




The following remains to be proven:
Dependency Pairs:

IFREACH1(false, x, y, edge(u, v, i), h) -> REACH(x, y, i, edge(u, v, h))
IFREACH2(false, x, y, edge(u, v, i), h) -> REACH(v, y, union(i, h), empty)
IFREACH2(false, x, y, edge(u, v, i), h) -> REACH(x, y, i, h)
IFREACH1(true, x, y, edge(u, v, i), h) -> IFREACH2(eq(y, v), x, y, edge(u, v, i), h)
REACH(x, y, edge(u, v, i), h) -> IFREACH1(eq(x, u), x, y, edge(u, v, i), h)


Rules:


eq(0, 0) -> true
eq(0, s(x)) -> false
eq(s(x), 0) -> false
eq(s(x), s(y)) -> eq(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) -> ifreach1(eq(x, u), x, y, edge(u, v, i), h)
ifreach1(true, x, y, edge(u, v, i), h) -> ifreach2(eq(y, v), x, y, edge(u, v, i), h)
ifreach1(false, x, y, edge(u, v, i), h) -> reach(x, y, i, edge(u, v, h))
ifreach2(true, x, y, edge(u, v, i), h) -> true
ifreach2(false, x, y, edge(u, v, i), h) -> or(reach(x, y, i, h), reach(v, y, union(i, h), empty))




Termination of R could not be shown.
Duration:
0:01 minutes