YES

# parallel critical pair closing system (Shintani and Hirokawa 2022, Section 8 in LMCS 2023)

Consider the left-linear TRS R:

  foo(0(x)) -> 0(s(p(p(p(s(s(s(p(s(x))))))))))
  foo(s(x)) -> p(s(p(p(p(s(s(p(s(s(p(s(foo(p(p(s(s(p(s(bar(p(p(s(s(p(s(x))))))))))))))))))))))))))
  bar(0(x)) -> 0(p(s(s(s(x)))))
  bar(s(x)) -> p(s(p(p(s(s(foo(s(p(p(s(s(x))))))))))))
  p(p(s(x))) -> p(x)
  p(s(x)) -> x
  p(0(x)) -> 0(s(s(s(s(x)))))

Let C be the following subset of R:

  foo(s(x)) -> p(s(p(p(p(s(s(p(s(s(p(s(foo(p(p(s(s(p(s(bar(p(p(s(s(p(s(x))))))))))))))))))))))))))
  bar(s(x)) -> p(s(p(p(s(s(foo(s(p(p(s(s(x))))))))))))
  p(s(x)) -> x

The TRS R is left-linear and all parallel critical pairs are joinable by C.
Therefore, the confluence of R is equivalent to that of C.

# parallel critical pair closing system (Shintani and Hirokawa 2022, Section 8 in LMCS 2023)

Consider the left-linear TRS R:

  foo(s(x)) -> p(s(p(p(p(s(s(p(s(s(p(s(foo(p(p(s(s(p(s(bar(p(p(s(s(p(s(x))))))))))))))))))))))))))
  bar(s(x)) -> p(s(p(p(s(s(foo(s(p(p(s(s(x))))))))))))
  p(s(x)) -> x

Let C be the following subset of R:

  (empty)

The TRS R is left-linear and all parallel critical pairs are joinable by C.
Therefore, the confluence of R is equivalent to that of C.

# emptiness

The empty TRS is confluent.