FA-63780 / Actuarial life tables / Member archive

Pure endowment and survivorship accumulation: Pure endowment is not discounted · case 05

nEx equals the survival probability.

Member previewVariant 5 · 3 implementations · 8 checks per implementation

Case contract

Input l (from issue age), n (0<=n<len(l) else 'invalid term'), i, g (premium escalation per mille), P. l_n=0 -> 'no survivors'. nEx = (l_n/l_0) v^n. Fund per survivor at n = sum_{k<n} P(1+g)^k (1+i)^(n-k) l_k/l_n (premiums at the start of each year). Return [nEx rounded 8, fund rounded half-up].

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
five-year accumulation	`[0.97408, 2471882]`	`[0.84024996, 2471882]`	Failed

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