YES

TRS:

  msort(nil()) -> nil()
  msort(.(x,y)) -> .(min(x,y),msort(del(min(x,y),.(x,y))))
  min(x,nil()) -> x
  min(x,.(y,z)) -> if(<=(x,y),min(x,z),min(y,z))
  del(x,nil()) -> nil()
  del(x,.(y,z)) -> if(=(x,y),z,.(y,del(x,z)))

linear polynomial interpretations on N:

  msort_A(x1) = x1 + 1
  msort#_A(x1) = x1 + 3
  nil_A = 1
  nil#_A = 0
  ._A(x1,x2) = x1 + 2
  .#_A(x1,x2) = x2 + 2
  min_A(x1,x2) = x1 + 1
  min#_A(x1,x2) = 1
  del_A(x1,x2) = 1
  del#_A(x1,x2) = 4
  if_A(x1,x2,x3) = 0
  if#_A(x1,x2,x3) = 0
  <=_A(x1,x2) = x2 + 1
  <=#_A(x1,x2) = 0
  =_A(x1,x2) = x1 + x2 + 1
  =#_A(x1,x2) = 0

precedence:

  msort > min = del > nil = . = if = <= = =