FA-13733 / Numerical aggregation / Member archive

Tie adjusted concordance squared: X tie correction counts tied pairs rather than varying pairs. · case 03

The reduction disagrees with its explicit aggregation oracle.

Member previewVariant 3 · 3 implementations · 8 checks per implementation

Case contract

For paired ordinal observations return sign(tau_b)*tau_b**2 as an exact Fraction string. Every unordered observation pair contributes its coordinate comparison; normalize signed concordance squared by products of non-tied x/y pair counts. Undefined if either coordinate has no varying pairs.

Why this case matters

Exact bounded examples isolate a reduction defect without floating-point or external-service effects.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
regression 1	`null`	`"1"`	Failed

MEMBER ARCHIVE

The complete case is available to members.

This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

Member access is invitation-based. Sign in with your invited account to inspect the sources.