Gate-Zero Growth: A Geometric Framework for Function-Preserving Continual Learning
Summary
Gate-zero growth introduces a function-preserving (FP) operator for continual learning, enabling the addition of new residual blocks via a zero-initialised gate. This mechanism induces rank separation in the functional Jacobian, ensuring old directions remain unchanged while new-weight directions are flat at the growth point. Function drift is controlled at O("||\u03b1||^2") and Jacobian leakage at O("||\u03b1||_\u221e"), allowing a controlled departure from the FP locus. Evaluated on a 300M\u2192857M Transformer adapted from WikiText-103 to BookCorpus, gate-zero growth achieved near-zero old-domain forgetting (\u0394_A < 0.1) under both Isolation and Freeze-Nothing operating points. This performance significantly outperforms a non-FP control, which suffered an order-of-magnitude larger forgetting. The geometric analysis also extends to LoRA, ReZero, and zero-init adapter constructions, positioning gate-zero growth as a canonical instance for safe capacity activation in continual learning.
Key takeaway
For machine learning engineers developing continual learning systems, this framework offers a robust solution to catastrophic forgetting. By implementing gate-zero growth, you can expand model capacity while preserving performance on previously learned tasks, achieving near-zero old-domain forgetting. Consider integrating this function-preserving operator to safely activate new capacity in your Transformer models, especially when adapting to new datasets like BookCorpus from WikiText-103.
Key insights
Function-preserving continual learning is achieved by adding zero-initialized gated residual blocks that control functional variation.
Principles
- Gate-zero growth induces rank separation in the functional Jacobian.
- Function drift is O("||\u03b1||^2") and Jacobian leakage O("||\u03b1||_\u221e").
- A shared local geometry governs safe capacity activation in continual learning.
Method
Gate-zero growth adds new residual blocks through a zero-initialised gate, ensuring old directions are unchanged and new functional variation is the only first-order source.
In practice
- Achieves \u0394_A < 0.1 old-domain forgetting on Transformers.
- Applicable under Isolation and Freeze-Nothing operating points.
- Covers LoRA, ReZero, and zero-init adapter constructions.
Topics
- Continual Learning
- Function-Preserving Operators
- Gate-Zero Growth
- Transformer Models
- Catastrophic Forgetting
- Jacobian Analysis
Best for: Research Scientist, AI Scientist, Machine Learning Engineer, NLP Engineer
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Editorial summary, takeaway, and curation by AIssential. Original article published by Artificial Intelligence.