# C740 — Recover LXX local changes from its boundary profile

## Question

Can adjacent differences identify the contributing rows and distinguish aninsertedrowfromalifespanchange?

## Inputs

```json
{
  "shared_edge": "Arphaxad→Shelah spansLXXCainan2",
  "profile": "LXXminusMT"
}
```

## Sources

```json
[
  "C739; File18 §§2,4,6D"
]
```

## Opened utc

2026-09-28T01:44:27.830408+00:00

## Results

```json
{
  "nonzero_edge_changes": {
    "R": {
      "Adam": 100,
      "Seth": 100,
      "Enosh": 100,
      "Kenan": 100,
      "Mahalalel": 100,
      "Enoch": 100,
      "Arphaxad": 230,
      "Shelah": 100,
      "Eber": 100,
      "Peleg": 100,
      "Reu": 100,
      "Serug": 100,
      "Nahor": 50
    },
    "C_lower": {
      "Lamech": -24,
      "Arphaxad": 487,
      "Shelah": 27,
      "Eber": 40,
      "Peleg": 100,
      "Reu": 100,
      "Serug": 100,
      "Nahor": 60
    },
    "G": {
      "Adam": -100,
      "Seth": -100,
      "Enosh": -100,
      "Kenan": -100,
      "Mahalalel": -100,
      "Enoch": -100,
      "Lamech": -24,
      "Arphaxad": 257,
      "Shelah": -73,
      "Eber": -60,
      "Nahor": 10
    }
  },
  "collapsed_Arphaxad_components": {
    "regular": [
      100,
      130
    ],
    "cumulative": [
      27,
      460
    ],
    "bridge": [
      -73,
      330
    ]
  }
}
```

## Finding

Finite differences recover the entireLXX change support. At the sharedArphaxad→Shelah edge, regular230 splits into100+130 and cumulative487 into27+460. KeepingCainan as a native row distinguishes insertion from the adjacent biography change; collapsing them would lose that explanation.

## Reassessment

Recover theSP support with its separateLamech completed-year correction.

## Checks

```json
{
  "regular_edge": true,
  "cumulative_edge": true,
  "bridge_edge": true,
  "Lamech": true
}
```

## Closed utc

2026-09-28T01:44:27.830588+00:00

## Record provenance

Exact record hash: `59fb0a0ff96c1a74ece3b0c733348845fd028c35e83a2781ffb1e574218a7092`

Source journal: `Research_Cycles/C0732_C0831/journal.json`