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Net premium reserve recursion: Negative reserves are floored at zero · case 03

Deficient-premium years show zero reserves and later reserves drift.

Member previewVariant 3 · 3 implementations · 7 checks per implementation

Case contract

Input q (per 100000 by policy year), P (annual net premium, cents, paid at start of year), S (death benefit at year end), i (per mille). Starting from 0V=0: (k+1)V = ((kV+P)(1+i) - q S)/p carried exactly; each reserve is reported rounded half away from zero. If p=0 report None and stop.

Why this case matters

Life-table arithmetic compounds across ages, so one misplaced index or assumption shifts every downstream value.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
level premium reserve build-up	`[0, 0, 0, 0, 0, 0]`	`[-37278, -91396, -166874, -263640, -390149, -548341]`	Failed

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