நம்பிக்கை சிதைவு வளைவுTrust-Decay Curve T(t)
Backward-looking audit of the Sri Lankan state's commitment-default record since the Indo-Lanka Accord.
T(t) = T₀ · exp(−λ·t), where λ increases discretely at each documented commitment-default event
§1What it measures
TDC is the most-misread of the five models. It is not a sentiment claim about how Tamils feel; it is an auditable record of formally adopted commitments and their formally documented non-implementation. The curve form is a presentational device — what matters is the discrete step series.
The point of the model is to convert 'why don't Tamils trust the Sri Lankan state's commitments?' from a vibes question into a citation question. Every λ step is a footnote.
§2Inputs & sources
Set at the 29 July 1987 Indo-Lanka Accord. This is a documentation choice; the Bandaranaike-Chelvanayakam Pact (1957) and Dudley-Chelvanayakam Pact (1965) are recorded earlier in the Narrowing Timeline and could be used as alternative anchors. T₀ is not a claim about pre-1987 trust.
- ◇Indo-Sri Lanka Agreement to Establish Peace and Normalcy in Sri Lanka (29 July 1987), Ministry of External Affairs (India)
λ increases by a documented step at each of: 1989 IPKF withdrawal without full 13A implementation; 2003 P-TOMS Supreme Court collapse; 2010 LLRC non-implementation; 2020 co-sponsorship withdrawal from A/HRC/RES/30/1; 2022 OMP non-prosecutorial mandate; successive PTA replacement bills (2018, 2023, 2024) not delivering substantive reform.
- ◇Goodhand, Spencer & Korf (eds.), Conflict and Peacebuilding in Sri Lanka (2011), Routledge
- ◇International Crisis Group — Sri Lanka country series
- ◇OHCHR Annual Reports on Sri Lanka
- ◇International Commission of Jurists briefings on the PTA
§3Worked reading
T(t) is dimensionless. Its presentational form (exponential) reflects the empirical observation that successive defaults compound — each unkept commitment makes the next one structurally harder to fund, sponsor, or believe.
The curve form should not be over-read. If the Sri Lankan state fully implements a single commitment with a measurable timeline and independent verification, λ would not step further and the model's trajectory would flatten. This is the meaning of the falsifier.
If any one of the listed commitment-default events is reversed by completed implementation with independent verification, the corresponding λ step is removed and TDC's trajectory is correspondingly revised. If two or more are reversed, the model's argumentative force is materially weakened.