FA-6133 / Polynomial arithmetic / Member archive

Quadratic discriminant · case 03

The product term uses addition instead of subtraction.

Member previewVariant 3 · 3 implementations · 4 checks per implementation

Case contract

Integer coefficients in ascending power order and integer evaluation bounds; missing high-degree coefficients are zero. Rational outputs are reduced Fraction strings; the zero-polynomial degree is -1. Quadratic discriminant. Exact operational definition: b*b-4*a*c

Why this case matters

Small exact fixtures expose this error without platform timing, external services, or probabilistic observations. Polynomial arithmetic results depend on the stated convention.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
fixture 1: (1, 0, -1)	`-4`	`4`	Failed

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