PROOF.c4.b: def of bend-kit-collections@0.1.4.1
Import: import bend-kit-collections@0.1.4.1/PROOF.bend as PROOF
Lines 92-96 of bend-kit-collections@0.1.4.1/PROOF.bend: https://jend.leeeet.dev/read.txt?path=bend-kit-collections@0.1.4.1/PROOF.bend&start_line=92&end_line=96

import Base
import bend-mathlib@0.7.4.0/bool.bend as MBool

def c4.b(
  +a: Bool, +b: Bool, +c: Bool, +d: Bool,
  e: {Bool.and(Bool.and(Bool.and(a, b), c), d) == True{} : Bool}
) -> {b == True{} : Bool}:
  MBool.eq_true_of_and_right(a, b, MBool.eq_true_of_and_left(Bool.and(a, b), c, MBool.eq_true_of_and_left(Bool.and(Bool.and(a, b), c), d, e)))

Uses (4):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool.and
  https://jend.leeeet.dev/definition.txt?path=bend-mathlib@0.8.1.0/bool.bend&name=eq_true_of_and_left
  https://jend.leeeet.dev/definition.txt?path=bend-mathlib@0.8.1.0/bool.bend&name=eq_true_of_and_right