# C1037 — Twin-arm terminal condition

## Question

What does the second161 arm add after the biographies are fixed?

## Inputs

```json
{}
```

## Sources

```json
[
  "File60 §3.2",
  "C1036"
]
```

## Opened utc

2026-09-28T04:03:41.802265+00:00

## Results

```json
{
  "arms": [
    161,
    161
  ],
  "terminal_required_by_symmetry": 1406,
  "retained_source_terminal": 1406,
  "A4_residual": 0
}
```

## Finding

With biographies fixed, twin arms impose one condition on the retained terminal. The terminal1406 is source-appointed; the calculation identifies its role rather than selecting it by search.

## Reassessment

Test Joseph’s span against that same terminal and its relationship to the other conditions.

## Checks

```json
{
  "twin_arms": true,
  "terminal_agrees": true
}
```

## Closed utc

2026-09-28T04:03:41.802869+00:00

## Record provenance

Exact record hash: `367da05e2f6c83cb0ac1bad440cb59947081ad4f8519777549768e5fe3cff193`

Source journal: `Research_Cycles/C0932_C1131/journal.json`