FA-16445 / Floating-point arithmetic / Member archive

Complex square root adds signed real part in its stable magnitude · case 05

Complex square root adds signed real part in its stable magnitude.

Member previewVariant 5 · 3 implementations · 10 checks per implementation

Case contract

Principal complex square root for finite components, using stable branch reconstruction and preserving the imaginary signed-zero side of the negative real branch cut. Fixtures keep hypot finite. Finite results are rendered to eleven significant decimal digits; modeled domain violations and arithmetic errors are explicit strings.

Why this case matters

An offline floating representation model isolates a reproducible arithmetic fault.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
negative axis above	`"arithmetic-error"`	`["0", "5"]`	Failed

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