FA-18705 / Time representation / Member archive

Civil fraction inherits signed remainder or unshifted day number · case 05

The decoded time state disagrees with the explicit regression oracle for fraction.

Member previewVariant 5 · 3 implementations · 12 checks per implementation

Case contract

Controlled astronomical coordinate counts exact rational days from a noon origin. A civil day index uses midnight; coordinate J corresponds to civil index floor(J+1/2) and fraction J+1/2-index. One civil day has 86400 exact ticks. Return civil index, rational tick within day, noon-relative displacement, modified coordinate J-2400000.5, exact roundtrip and before-noon flag. No historical calendar conversion is modeled.

Why this case matters

Clock transfer and timestamp consumers require preserved coordinate, phase, validity and elapsed-time semantics.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
fixture 6	`[-1, "-21600", "-64800", "-9600005/4", "-7/4", true, "-1", "-21600"]`	`[-1, "64800", "21600", "-9600005/4", "-3/4", false, "0", "64800"]`	Failed

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