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Mihalis Nicolaou

8 accepted papers

2026

Neural Collapse by Design: Learning Class Prototypes on the Hypersphere

ICML 2026poster

Supervised classifier learning has a theoretical optimum — Neural Collapse (NC) — yet standard training does not reach it in practice. We trace this failure to a geometric limitation: cross-entropy is invariant to joint rescaling of features and weights, leaving radial degrees of freedom unconstrain…

Cited by 0SourceScholar
2026

PolySAE: Modeling Feature Interactions in Sparse Autoencoders via Polynomial Decoding

ICML 2026poster

Sparse autoencoders (SAEs) have emerged as a promising method for interpreting neural network representations by decomposing activations into sparse combinations of dictionary atoms. However, SAEs assume that features combine additively through linear reconstruction, an assumption that cannot captur…

Cited by 0SourceScholar
2025

Towards Interpretability Without Sacrifice: Faithful Dense Layer Decomposition with Mixture of Decoders

NeurIPS 2025poster

Multilayer perceptrons (MLPs) are an integral part of large language models, yet their dense representations render them difficult to understand, edit, and steer. Recent methods learn interpretable approximations via neuron-level sparsity, yet fail to faithfully reconstruct the original mapping--sig…

Cited by 0SourcecodeScholar
2024

Bridging Mini-Batch and Asymptotic Analysis in Contrastive Learning: From InfoNCE to Kernel-Based Losses

ICML 2024poster

What do different contrastive learning (CL) losses actually optimize for? Although multiple CL methods have demonstrated remarkable representation learning capabilities, the differences in their inner workings remain largely opaque. In this work, we analyse several CL families and prove that, under…

2024

Multilinear Mixture of Experts: Scalable Expert Specialization through Factorization

NeurIPS 2024poster

The Mixture of Experts (MoE) paradigm provides a powerful way to decompose dense layers into smaller, modular computations often more amenable to human interpretation, debugging, and editability. However, a major challenge lies in the computational cost of scaling the number of experts high enough t…

2023

PandA: Unsupervised Learning of Parts and Appearances in the Feature Maps of GANs

ICLR 2023poster

Recent advances in the understanding of Generative Adversarial Networks (GANs) have led to remarkable progress in visual editing and synthesis tasks, capitalizing on the rich semantics that are embedded in the latent spaces of pre-trained GANs. However, existing methods are often tailored to specifi…

2023

Parts of Speech–Grounded Subspaces in Vision-Language Models

NeurIPS 2023poster

Latent image representations arising from vision-language models have proved immensely useful for a variety of downstream tasks. However, their utility is limited by their entanglement with respect to different visual attributes. For instance, recent work has shown that CLIP image representations ar…

2022

Efficient Learning of Multiple NLP Tasks via Collective Weight Factorization on BERT

NAACL 2022findings

The Transformer architecture continues to show remarkable performance gains in many Natural Language Processing tasks. However, obtaining such state-of-the-art performance in different tasks requires fine-tuning the same model separately for each task. Clearly, such an approach is demanding in terms…

Cited by 3SourcePDFScholar