FA-5685 / Combinatorics / Member archive
Positive composition count · case 05
Zero components are admitted in a positive composition.
Case contract
Nonnegative integer counts. Permutation and combination counts are zero when a requested selection exceeds the available objects. Shape sizes satisfy the preconditions stated below. parts>=1; count ordered vectors of parts strictly positive integers summing to n. Exact operational definition: math.comb(n-1,parts-1) if n>=parts else 0
Why this case matters
Small exact fixtures expose this error without platform timing, external services, or probabilistic observations. Combinatorics results depend on the stated convention.
One recorded failure
Sample boundary fixtureThis sample comes from the broken implementation of a controlled reproducer.
| Boundary fixture | Actual | Expected | Outcome |
|---|---|---|---|
| fixture 1: (5, 2) | 6 | 4 | Failed |
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