Lottery Ticket Hypothesis

Creator
Creator
Seonglae ChoSeonglae Cho
Created
Created
2025 Jan 20 12:10
Editor
Edited
Edited
2026 Mar 3 15:38

LTH

The hypothesis states that within a large neural network, there exists a small, sparse subnetwork (a "winning ticket") that, when trained in isolation with its original initialization weights (or values very close to them), can match the performance of the full network.
  • Randomly initialized large network ⟶ training ⟶ pruning
  • Certain subnetworks retrained with original initialization weights still maintain performance
  • Performance heavily depends on "structure + initialization"
 
 
 
 
arxiv.org

MLP Interpretability

A paper explaining the internal mechanism of the
Grokking
phenomenon in small neural networks learning modular addition through Fourier features + lottery ticket structure + phase alignment process. What the model actually learns: when a two-layer neural network solves modular addition, each neuron learns a single-frequency Fourier feature. In other words, it solves the problem by transforming it into a periodic signal decomposition problem rather than arithmetic. Previous research only discovered that "neurons learn frequencies," but this paper explains how those features are combined into a complete algorithm and why generalization suddenly occurs. Modular addition is special because it can be completely expressed with Fourier bases, making it possible to precisely analyze the internal mechanism, which is why it was chosen as a toy model.
After the memorization phase, phase alignment aligns the frequencies' phases, causing the entire structure to operate like a single algorithm. Then grokking occurs with an explosion in generalization performance. In other words,
Grokking
is not about feature discovery but rather about alignment or composition of already-discovered features.
Similar to the
Lottery Ticket Hypothesis
, there already exists a subnetwork within the network that can implement the correct algorithm. Learning is the process of "activating" that structure.
arxiv.org
 

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