# C903 — Contrast whole-frame motion with source-fixed anchor change

## Question

Why are some paired fields rigid translations while File52c is not?

## Inputs

```json
{}
```

## Sources

```json
[
  "C852–858",
  "C868",
  "C893",
  "C839"
]
```

## Opened utc

2026-09-28T02:54:42.207709+00:00

## Results

```json
{
  "comparison": {
    "path": "model/frame_vs_anchor_change.json",
    "sha256": "c480a3cf3b943f4779a68c30de4e713baba009c64cc59d481640dea0af4a0ecf",
    "bytes": 398
  },
  "original_spans_preserved": 64,
  "different_inverse_gaps": 19
}
```

## Finding

Whole-frame covariance applies across the new objects because their relative inputs remain fixed. File52c changes only the anchor while holding the source date, so its measured span and digit branch change. This explains rigid NT/carrier translations versus the nonuniform paired inverse field.

## Reassessment

Classify every festival prefix against the49/70 common measure.

## Checks

```json
{
  "all64_original_spans": true,
  "nonuniform": true
}
```

## Closed utc

2026-09-28T02:54:42.208557+00:00

## Record provenance

Exact record hash: `492cf753f0ae04023cc08b125ac22589da3991802da7b20d473439859255ae6f`

Source journal: `Research_Cycles/C0832_C0931/journal.json`