Util.binomial: def of unified-nsga-iii@0.2.2.0
Import: import unified-nsga-iii@0.2.2.0/util.bend as Util
Lines 60-68 of unified-nsga-iii@0.2.2.0/util.bend: https://jend.leeeet.dev/read.txt?path=unified-nsga-iii@0.2.2.0/util.bend&start_line=60&end_line=68

import Base

# C(n, k). Das–Dennis count = C(p + M - 1, M - 1).
def binomial(+n: Nat, +k: Nat) -> Nat:
  match n k:
    case x 0n:
      1n
    case 0n 1n+pk:
      0n
    case 1n+pn 1n+pk:
      Nat.add(binomial(pn, pk), binomial(pn, 1n+pk))

Uses (2):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.add