YES
We show the termination of the TRS R:

  app(app(plus(),|0|()),y) -> y
  app(app(plus(),app(s(),x)),y) -> app(s(),app(app(plus(),x),y))
  app(app(times(),|0|()),y) -> |0|()
  app(app(times(),app(s(),x)),y) -> app(app(plus(),app(app(times(),x),y)),y)
  app(app(app(comp(),f),g),x) -> app(f,app(g,x))
  app(twice(),f) -> app(app(comp(),f),f)

Instead we prove termination of the uncurried system:

  app(comp_0(),y) -> comp_1(y)
  app(comp_1(x1),y) -> comp_2(x1,y)
  app(comp_2(x1,x2),y) -> comp_3(x1,x2,y)
  app(plus_0(),y) -> plus_1(y)
  app(plus_1(x1),y) -> plus_2(x1,y)
  app(s_0(),y) -> s_1(y)
  app(times_0(),y) -> times_1(y)
  app(times_1(x1),y) -> times_2(x1,y)
  app(twice_0(),y) -> twice_1(y)
  plus_2(|0|_0(),y) -> y
  plus_2(s_1(x),y) -> s_1(plus_2(x,y))
  times_2(|0|_0(),y) -> |0|_0()
  times_2(s_1(x),y) -> plus_2(times_2(x,y),y)
  comp_3(f,g,x) -> app(f,app(g,x))
  twice_1(f) -> comp_2(f,f)


-- SCC decomposition.

Consider the dependency pair problem (P, R), where P consists of

p1: app#(comp_2(x1,x2),y) -> comp_3#(x1,x2,y)
p2: app#(plus_1(x1),y) -> plus_2#(x1,y)
p3: app#(times_1(x1),y) -> times_2#(x1,y)
p4: app#(twice_0(),y) -> twice_1#(y)
p5: plus_2#(s_1(x),y) -> plus_2#(x,y)
p6: times_2#(s_1(x),y) -> plus_2#(times_2(x,y),y)
p7: times_2#(s_1(x),y) -> times_2#(x,y)
p8: comp_3#(f,g,x) -> app#(f,app(g,x))
p9: comp_3#(f,g,x) -> app#(g,x)

and R consists of:

r1: app(comp_0(),y) -> comp_1(y)
r2: app(comp_1(x1),y) -> comp_2(x1,y)
r3: app(comp_2(x1,x2),y) -> comp_3(x1,x2,y)
r4: app(plus_0(),y) -> plus_1(y)
r5: app(plus_1(x1),y) -> plus_2(x1,y)
r6: app(s_0(),y) -> s_1(y)
r7: app(times_0(),y) -> times_1(y)
r8: app(times_1(x1),y) -> times_2(x1,y)
r9: app(twice_0(),y) -> twice_1(y)
r10: plus_2(|0|_0(),y) -> y
r11: plus_2(s_1(x),y) -> s_1(plus_2(x,y))
r12: times_2(|0|_0(),y) -> |0|_0()
r13: times_2(s_1(x),y) -> plus_2(times_2(x,y),y)
r14: comp_3(f,g,x) -> app(f,app(g,x))
r15: twice_1(f) -> comp_2(f,f)

The estimated dependency graph contains the following SCCs:

  {p1, p8, p9}
  {p7}
  {p5}


-- Reduction pair.

Consider the dependency pair problem (P, R), where P consists of

p1: app#(comp_2(x1,x2),y) -> comp_3#(x1,x2,y)
p2: comp_3#(f,g,x) -> app#(g,x)
p3: comp_3#(f,g,x) -> app#(f,app(g,x))

and R consists of:

r1: app(comp_0(),y) -> comp_1(y)
r2: app(comp_1(x1),y) -> comp_2(x1,y)
r3: app(comp_2(x1,x2),y) -> comp_3(x1,x2,y)
r4: app(plus_0(),y) -> plus_1(y)
r5: app(plus_1(x1),y) -> plus_2(x1,y)
r6: app(s_0(),y) -> s_1(y)
r7: app(times_0(),y) -> times_1(y)
r8: app(times_1(x1),y) -> times_2(x1,y)
r9: app(twice_0(),y) -> twice_1(y)
r10: plus_2(|0|_0(),y) -> y
r11: plus_2(s_1(x),y) -> s_1(plus_2(x,y))
r12: times_2(|0|_0(),y) -> |0|_0()
r13: times_2(s_1(x),y) -> plus_2(times_2(x,y),y)
r14: comp_3(f,g,x) -> app(f,app(g,x))
r15: twice_1(f) -> comp_2(f,f)

The set of usable rules consists of

  r10, r12

Take the reduction pair:

  generalized weighted path order (>=MG, >G)
  
    base order 1:
  
      matrix interpretation with standard point-wise order:
      
        carrier: N^1
        order: standard order
        interpretations:
          app#_A(x1,x2) = x1
          comp_2_A(x1,x2) = x1 + x2 + 2
          comp_3#_A(x1,x2,x3) = x1 + x2 + 1
          app_A(x1,x2) = 5
          plus_2_A(x1,x2) = x2 + 2
          |0|_0_A() = 1
          times_2_A(x1,x2) = x1 + 3
  
    base order 2:
  
      marked-algebra reduction triple (>=A, >=A!, >A!):
      
        matrix interpretation with standard point-wise order:
        
          carrier: N^1
          order: standard order
          interpretations:
            app#_A(x1,x2) = 0
            comp_2_A(x1,x2) = x2
            comp_3#_A(x1,x2,x3) = 0
            app_A(x1,x2) = x2
            plus_2_A(x1,x2) = x1 + x2 + 1
            |0|_0_A() = 0
            times_2_A(x1,x2) = 0
            app#!_A(x1,x2) = 0
            comp_2!_A(x1,x2) = x1 + 2
            comp_3#!_A(x1,x2,x3) = x2 + 1
            app!_A(x1,x2) = x2 + 4
            plus_2!_A(x1,x2) = 7
            |0|_0!_A() = 2
            times_2!_A(x1,x2) = x2 + 2
  
    partial status:
  
      pi(app#) = [1]
      pi(comp_2) = []
      pi(comp_3#) = []
      pi(app) = []
      pi(plus_2) = [2]
      pi(|0|_0) = []
      pi(times_2) = []

The following rules are removed:

  p1, p2, p3

Then no dependency pair remains.

-- Reduction pair.

Consider the dependency pair problem (P, R), where P consists of

p1: times_2#(s_1(x),y) -> times_2#(x,y)

and R consists of:

r1: app(comp_0(),y) -> comp_1(y)
r2: app(comp_1(x1),y) -> comp_2(x1,y)
r3: app(comp_2(x1,x2),y) -> comp_3(x1,x2,y)
r4: app(plus_0(),y) -> plus_1(y)
r5: app(plus_1(x1),y) -> plus_2(x1,y)
r6: app(s_0(),y) -> s_1(y)
r7: app(times_0(),y) -> times_1(y)
r8: app(times_1(x1),y) -> times_2(x1,y)
r9: app(twice_0(),y) -> twice_1(y)
r10: plus_2(|0|_0(),y) -> y
r11: plus_2(s_1(x),y) -> s_1(plus_2(x,y))
r12: times_2(|0|_0(),y) -> |0|_0()
r13: times_2(s_1(x),y) -> plus_2(times_2(x,y),y)
r14: comp_3(f,g,x) -> app(f,app(g,x))
r15: twice_1(f) -> comp_2(f,f)

The set of usable rules consists of

  (no rules)

Take the reduction pair:

  generalized weighted path order (>=MG, >G)
  
    base order 1:
  
      matrix interpretation with standard point-wise order:
      
        carrier: N^1
        order: standard order
        interpretations:
          times_2#_A(x1,x2) = x1
          s_1_A(x1) = x1 + 2
  
    base order 2:
  
      marked-algebra reduction triple (>=A, >=A!, >A!):
      
        matrix interpretation with standard point-wise order:
        
          carrier: N^1
          order: standard order
          interpretations:
            times_2#_A(x1,x2) = x1
            s_1_A(x1) = x1 + 2
            times_2#!_A(x1,x2) = x1 + 5
            s_1!_A(x1) = x1 + 4
  
    partial status:
  
      pi(times_2#) = []
      pi(s_1) = [1]

The following rules are removed:

  p1

Then no dependency pair remains.

-- Reduction pair.

Consider the dependency pair problem (P, R), where P consists of

p1: plus_2#(s_1(x),y) -> plus_2#(x,y)

and R consists of:

r1: app(comp_0(),y) -> comp_1(y)
r2: app(comp_1(x1),y) -> comp_2(x1,y)
r3: app(comp_2(x1,x2),y) -> comp_3(x1,x2,y)
r4: app(plus_0(),y) -> plus_1(y)
r5: app(plus_1(x1),y) -> plus_2(x1,y)
r6: app(s_0(),y) -> s_1(y)
r7: app(times_0(),y) -> times_1(y)
r8: app(times_1(x1),y) -> times_2(x1,y)
r9: app(twice_0(),y) -> twice_1(y)
r10: plus_2(|0|_0(),y) -> y
r11: plus_2(s_1(x),y) -> s_1(plus_2(x,y))
r12: times_2(|0|_0(),y) -> |0|_0()
r13: times_2(s_1(x),y) -> plus_2(times_2(x,y),y)
r14: comp_3(f,g,x) -> app(f,app(g,x))
r15: twice_1(f) -> comp_2(f,f)

The set of usable rules consists of

  (no rules)

Take the reduction pair:

  generalized weighted path order (>=MG, >G)
  
    base order 1:
  
      matrix interpretation with standard point-wise order:
      
        carrier: N^1
        order: standard order
        interpretations:
          plus_2#_A(x1,x2) = x1
          s_1_A(x1) = x1 + 2
  
    base order 2:
  
      marked-algebra reduction triple (>=A, >=A!, >A!):
      
        matrix interpretation with standard point-wise order:
        
          carrier: N^1
          order: standard order
          interpretations:
            plus_2#_A(x1,x2) = x1
            s_1_A(x1) = x1 + 2
            plus_2#!_A(x1,x2) = x1 + 5
            s_1!_A(x1) = x1 + 4
  
    partial status:
  
      pi(plus_2#) = []
      pi(s_1) = [1]

The following rules are removed:

  p1

Then no dependency pair remains.