MAYBE

DP problem for innermost termination.
P =
  f5#(x1, x2, x3, x4) -> f4#(x1, x2, x3, x4) 
  f4#(I0, I1, I2, I3) -> f2#(I0, I1, I2, I3) 
  f3#(I4, I5, I6, I7) -> f1#(I4, I5, I6, I7) [I5 = I5]
  f2#(I8, I9, I10, I11) -> f3#(I8, I9, I10, I11) [I8 = I8]
  f1#(I12, I13, I14, I15) -> f2#(I12, I13, I14, -1 + I15) [2 - I15 <= I14 /\ I15 <= I14]
  f1#(I16, I17, I18, I19) -> f2#(I16, I17, -1 + I18, I19) [1 + I19 <= I18 /\ I19 <= 1 - I18]
  f1#(I20, I21, I22, I23) -> f2#(I20, I21, I22, 1 + I23) [1 + I22 <= -1 * I23 /\ I22 <= I23]
  f1#(I24, I25, I26, I27) -> f2#(I24, I25, 1 + I26, I27) [1 + I26 <= I27 /\ -1 * I26 <= I27]
R = 
  f5(x1, x2, x3, x4) -> f4(x1, x2, x3, x4) 
  f4(I0, I1, I2, I3) -> f2(I0, I1, I2, I3) 
  f3(I4, I5, I6, I7) -> f1(I4, I5, I6, I7) [I5 = I5]
  f2(I8, I9, I10, I11) -> f3(I8, I9, I10, I11) [I8 = I8]
  f1(I12, I13, I14, I15) -> f2(I12, I13, I14, -1 + I15) [2 - I15 <= I14 /\ I15 <= I14]
  f1(I16, I17, I18, I19) -> f2(I16, I17, -1 + I18, I19) [1 + I19 <= I18 /\ I19 <= 1 - I18]
  f1(I20, I21, I22, I23) -> f2(I20, I21, I22, 1 + I23) [1 + I22 <= -1 * I23 /\ I22 <= I23]
  f1(I24, I25, I26, I27) -> f2(I24, I25, 1 + I26, I27) [1 + I26 <= I27 /\ -1 * I26 <= I27]

The dependency graph for this problem is:
  0 -> 1
  1 -> 3
  2 -> 4, 5, 6, 7
  3 -> 2
  4 -> 3
  5 -> 3
  6 -> 3
  7 -> 3
Where:
  0) f5#(x1, x2, x3, x4) -> f4#(x1, x2, x3, x4) 
  1) f4#(I0, I1, I2, I3) -> f2#(I0, I1, I2, I3) 
  2) f3#(I4, I5, I6, I7) -> f1#(I4, I5, I6, I7) [I5 = I5]
  3) f2#(I8, I9, I10, I11) -> f3#(I8, I9, I10, I11) [I8 = I8]
  4) f1#(I12, I13, I14, I15) -> f2#(I12, I13, I14, -1 + I15) [2 - I15 <= I14 /\ I15 <= I14]
  5) f1#(I16, I17, I18, I19) -> f2#(I16, I17, -1 + I18, I19) [1 + I19 <= I18 /\ I19 <= 1 - I18]
  6) f1#(I20, I21, I22, I23) -> f2#(I20, I21, I22, 1 + I23) [1 + I22 <= -1 * I23 /\ I22 <= I23]
  7) f1#(I24, I25, I26, I27) -> f2#(I24, I25, 1 + I26, I27) [1 + I26 <= I27 /\ -1 * I26 <= I27]

We have the following SCCs.
  { 2, 3, 4, 5, 6, 7 }

DP problem for innermost termination.
P =
  f3#(I4, I5, I6, I7) -> f1#(I4, I5, I6, I7) [I5 = I5]
  f2#(I8, I9, I10, I11) -> f3#(I8, I9, I10, I11) [I8 = I8]
  f1#(I12, I13, I14, I15) -> f2#(I12, I13, I14, -1 + I15) [2 - I15 <= I14 /\ I15 <= I14]
  f1#(I16, I17, I18, I19) -> f2#(I16, I17, -1 + I18, I19) [1 + I19 <= I18 /\ I19 <= 1 - I18]
  f1#(I20, I21, I22, I23) -> f2#(I20, I21, I22, 1 + I23) [1 + I22 <= -1 * I23 /\ I22 <= I23]
  f1#(I24, I25, I26, I27) -> f2#(I24, I25, 1 + I26, I27) [1 + I26 <= I27 /\ -1 * I26 <= I27]
R = 
  f5(x1, x2, x3, x4) -> f4(x1, x2, x3, x4) 
  f4(I0, I1, I2, I3) -> f2(I0, I1, I2, I3) 
  f3(I4, I5, I6, I7) -> f1(I4, I5, I6, I7) [I5 = I5]
  f2(I8, I9, I10, I11) -> f3(I8, I9, I10, I11) [I8 = I8]
  f1(I12, I13, I14, I15) -> f2(I12, I13, I14, -1 + I15) [2 - I15 <= I14 /\ I15 <= I14]
  f1(I16, I17, I18, I19) -> f2(I16, I17, -1 + I18, I19) [1 + I19 <= I18 /\ I19 <= 1 - I18]
  f1(I20, I21, I22, I23) -> f2(I20, I21, I22, 1 + I23) [1 + I22 <= -1 * I23 /\ I22 <= I23]
  f1(I24, I25, I26, I27) -> f2(I24, I25, 1 + I26, I27) [1 + I26 <= I27 /\ -1 * I26 <= I27]