How statement and proof provenance work
The first chip identifies the source of the statement or construction; the second identifies the source of its local proof or verification.
- Literature-sourced: the exact statement appears in a cited source; only wording and notation differ.
- AI-adapted: a semantically identical restatement of literature-sourced material, modulo indexing, notation, and boundary cases adopted by the library.
- AI-generated: a genuinely novel statement formulated by AI, with no source for the claim itself.
These labels describe origin, not correctness: citations and verification chips remain separate evidence.
p4 and p4m orientation-indexed feature maps
Example
Let be the quarter-turn, a reflection, , and ; define when and otherwise. The ordinary planar cross-correlation with and is not rotation-equivariant with a fixed filter: , but and . In a p4 group layer, the feature map is indexed by pairs , giving four orientation indices at each translation ; in a p4m group layer it is indexed by for , giving eight. The full p4 and p4m groups remain infinite through their translations, and their group-correlation layers are equivariant for the full left action.
Example references
the p4 and p4m groups and their finite point groups
the action on spatial and group-indexed maps
planar cross-correlation convention
group-correlation equivariance
Cohen and Welling, “Group Equivariant Convolutional Networks,” §§4.2–4.4, 5–6.1 and Appendix A
Goodfellow, Bengio, and Courville, Deep Learning, Chapter 9 §§9.1–9.2 and §9.5
Facts & Assumptions
Given: The p4/p4m groups, feature-map actions, planar correlation, and group-correlation theorem described in the Example. Verify the orientation counts, group-layer equivariance, and fixed-filter rotation failure.
The p4 and p4m square-lattice symmetry groups: The point groups are and ; the full groups contain every translation and are infinite.
The left action on feature maps induced by an action on sites: The action on a feature map is .
Discrete convolutional layer with local receptive fields, channel mixing, stride, and padding: On the full lattice with unit stride, a finite receptive-field layer computes a discrete cross-correlation without kernel reversal.
First-layer and group-to-group cross-correlation: Group-to-group cross-correlation uses .
Group cross-correlation and compatible layers are equivariant: Group-to-group cross-correlation commutes with the left action whenever its sum is finite or absolutely convergent.
Verification
At a fixed translation , the p4 index has the four values and p4m has the eight distinct values , by [F1]. Distinct translations give infinitely many full group elements in each case.
For either full group or , apply [F5] to the group-correlation operator in [F4]. Its input and output actions are the left actions in [F2], so every such group layer is equivariant without treating as finite.
Since , . In the displayed planar correlation, only contributes, and , so . Therefore , whereas . As , these outputs differ.
Depends on
- The p4 and p4m square-lattice symmetry groups
- The left action on feature maps induced by an action on sites
- Discrete convolutional layer with local receptive fields, channel mixing, stride, and padding
- First-layer and group-to-group cross-correlation
- Group cross-correlation and compatible layers are equivariant
Used by
Nothing in the library uses this result yet.
Dependency tree · two levels
13 results within two dependency steps of this one, each drawn at its shortest distance from it. An arrow runs from a result to what uses it, so the chart reads left to right and ends at this result, which carries a heavier outline. Every node is a link to that result. Click elsewhere on the chart to enlarge it.
Sources
- Taco S. Cohen and Max Welling, Group Equivariant Convolutional Networks (standard reference, not scraped)
- Ian Goodfellow, Yoshua Bengio, and Aaron Courville, Deep Learning (standard reference, not scraped)