Term Rewriting System R:
[X, Y]
ackin(s(X), s(Y)) -> u21(ackin(s(X), Y), X)
u21(ackout(X), Y) -> u22(ackin(Y, X))
Innermost Termination of R to be shown.
   R
     ↳Dependency Pair Analysis
R contains the following Dependency Pairs: 
ACKIN(s(X), s(Y)) -> U21(ackin(s(X), Y), X)
ACKIN(s(X), s(Y)) -> ACKIN(s(X), Y)
U21(ackout(X), Y) -> ACKIN(Y, X)
Furthermore, R contains one SCC.
   R
     ↳DPs
       →DP Problem 1
         ↳Usable Rules (Innermost)
Dependency Pair:
ACKIN(s(X), s(Y)) -> ACKIN(s(X), Y)
Rules:
ackin(s(X), s(Y)) -> u21(ackin(s(X), Y), X)
u21(ackout(X), Y) -> u22(ackin(Y, X))
Strategy:
innermost
As we are in the innermost case, we can delete all 2 non-usable-rules.
   R
     ↳DPs
       →DP Problem 1
         ↳UsableRules
           →DP Problem 2
             ↳Size-Change Principle
Dependency Pair:
ACKIN(s(X), s(Y)) -> ACKIN(s(X), Y)
Rule:
none
Strategy:
innermost
We number the DPs as follows: 
- ACKIN(s(X), s(Y)) -> ACKIN(s(X), Y)
and get the following Size-Change Graph(s):
which lead(s) to this/these maximal multigraph(s): 
DP: empty set
Oriented Rules: none
We used the order Homeomorphic Embedding Order with Non-Strict Precedence.
trivial
 with Argument Filtering System:
s(x1) -> s(x1)
We obtain no new DP problems.
Innermost Termination of R successfully shown.
Duration: 
0:00 minutes