# C518 — The330 interface between source row and rounded geometry

## Question

What does the shared330 explain, and what does it leave as source placement?

## Inputs

```json
{
  "Cainan_b": 130,
  "Cainan_remainder": 330,
  "Cainan_lifespan": 460,
  "trio_outer_width": 7590
}
```

## Sources

```json
[
  "Strategy §§3.2,4.4",
  "File52c §3.12",
  "C488,C516–C517"
]
```

## Opened utc

2026-09-27T22:49:45.247059+00:00

## Results

```json
{
  "cross_mode_bridge_increment": 330,
  "trio_width_in_remainders": 23,
  "expanded_width": 8250,
  "gain_in_remainders": 2,
  "relations": [
    "inserting the row changes C−R by330",
    "supplied inverse trio has width23*330",
    "E sends23*330 to25*330"
  ]
}
```

## Finding

The same remainder measures the difference between Cainan’s two chronological projections and the trio’s23→25 width unit. This is a concrete interface between genealogical and rounded/calendar modules. The source inversions supplying23 copies are an additional placement fact; the row identity alone cannot predict them.

## Reassessment

Test the countdown’s460/430 pair as another reuse of the calendar module.

## Checks

```json
{
  "remainder": true,
  "width": true,
  "gain": true
}
```

## Closed utc

2026-09-27T22:49:45.247690+00:00

## Record provenance

Exact record hash: `a2abb5600a9a91f3fb5abb6e7f515d545f8f7d41abd5eee2ea116a18ee64938f`

Source journal: `Research_Cycles/C0482_C0531/journal.json`