Future Value (Lump Sum) mechanism

Model scope

The lump-sum future-value formula is correct under the stated unit assumptions. Verdict is NEEDS_REVIEW because the exact ambiguity is the undefined formula and sampling convention for the advertised growth curve, plus the absent definition of total growth. The honest label appropriately identifies the educational nature and omission of taxes and fees.

• The core formula FV=PV(1+r/n)^(nt) is standard for a nominal annual interest rate r compounded n times per year, with t measured in years.
• The specification does not define a formula or representation for total growth; the usual definition is total growth=FV-PV.
• The specification does not define the sampling interval, time points, or formula used for the growth curve, so that output cannot be verified unambiguously.

Units and conventions

• r must be supplied as a decimal fraction, such as 0.05 for 5% per year, not as the number 5.
• r is assumed to be a nominal annual rate.
• n is assumed to be a positive integer with units of compounding periods per year.
• t is measured in years; therefore nt is the total number of compounding periods.
• PV and FV must use the same currency units.
• The test-vector total_growth value is defined as FV-PV.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "PV": 1000,
    "r": 0.08,
    "n": 4,
    "t": 2
  },
  "expected_outputs": {
    "FV": 1171.659381004512,
    "total_growth": 171.659381004512
  },
  "working": "Periodic rate = r/n = 0.08/4 = 0.02. Total periods = n*t = 4*2 = 8. Growth factor = (1+0.02)^8 = 1.02^8 = 1.171659381004512. FV = 1000*1.171659381004512 = 1171.659381004512. Total growth = FV-PV = 1171.659381004512-1000 = 171.659381004512."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The n=0 vector produces an undefined division by zero. The instrument should reject n=0 before evaluating the formula; accepting it would create an undefined result or implementation-dependent behavior.

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche2/batch10-output.jsonl
• BOUNDARY_HAZARD_CATALOG.json