03

What survives the mask?

Mask placement changes available context. A fixed reconstruction table does not measure how hard a model would find it.

Hide one row. Then hide its neighbors.

First hide B. A, C and D still have their original rows. Now hide B, C and D together. B remains connected to all three neighbors, but only A still provides its original row directly. C and D provide mask-token inputs at the encoder's first layer.

FIG-003The connections stay. The visible original rows change.
Mask B onlyNodes A to F; edges AB, BC, BD, DE, EF, CF. Masked feature rows: B. Dashed circles denote masked rows; all nodes and edges remain.A(2, 1)BMASKC(2, 2)D(3, 1)E(1, 3)F(2, 3)

B hidden

Visible original neighbors of B: A, C, D.

Mask B, C and DNodes A to F; edges AB, BC, BD, DE, EF, CF. Masked feature rows: B, C, D. Dashed circles denote masked rows; all nodes and edges remain.A(2, 1)BMASKCMASKDMASKE(1, 3)F(2, 3)

B, C, D hidden

Visible original neighbors of B: A.

Dashed circles mark hidden feature rows. C and D still exist and can relay latent messages; this count describes first-layer original inputs only. CL-012, CL-018.

The distinction is between a neighbor existing and that neighbor's original features being visible. With multiple message-passing layers, context can travel farther: C connects to F, and D to E. Repeated aggregation expands the paths through which information can influence B. It does not make missing features recoverable by definition.

CL-012 · The comparison counts visible original feature rows. It is not a measured masking-difficulty curve.

A mask ratio leaves out its location

Our masks select one, two, or three of six nodes: approximately 16.7%, 33.3%, and 50%. These are teaching states, not a recommended schedule. Two masks of the same size can preserve different neighborhoods and different signals.

Holding a prediction fixed while changing the scored mask asks: which errors are averaged? Retraining under different masking policies asks: what representations does that learning process produce? The second needs controlled runs, a downstream task, and uncertainty estimates. The first can be answered exactly in a browser.

Define the prediction-time information boundary before pretraining. If an evaluation claims new-graph generalization, using that test graph during pretraining changes the claim, even without labels. A same-graph transductive protocol can be valid; it needs to be named.

CL-010 · Author inductive entry point; evaluation advice here is a qualified inference

Using edges is not reconstructing edges

Our edges determine message-passing neighborhoods. The target remains a feature row such as (1,2)(1,2). We do not predict whether AB or BC exists. Edge reconstruction needs its own target, output, and objective.

The original GraphMAE paper and reviewed core graphmae/models/edcoder.py path focus on features. There is an optional edge-masking loss branch in the repository's separate chemistry pretraining script. That detail is a reason to name the exact path and configuration, rather than infer behavior from a project name.

CL-001 · GraphMAE, original objective

CL-016 · Separate chemistry script, optional mask_edge branch

We now have the target and scoring set. The remaining choice is what it means for a reconstructed row to match.