collaborators

5 papers

cs.AI2026

Where does Absolute Position come from in decoder-only Transformers?

Valeria Ruscio, Umberto Nanni, Fabrizio Silvestri

RoPE-trained transformers distinguish absolute position in their attention patterns, even though RoPE encodes only relative offsets in the inner product. We trace this leakage to t…

cs.LG2026

Where Pretraining writes and Alignment reads: the asymmetry of Transformer weight space

Valeria Ruscio, Eli-Shaoul Khedouri, Keiran Thompson

Cross-entropy pretraining and preference alignment update the same transformer weights, but leave geometrically distinct traces. We characterise this asymmetry with a relative-subs…

cs.AI2026

The Phenomenology of Hallucinations

Valeria Ruscio, Keiran Thompson

We show that language models hallucinate not because they fail to detect uncertainty, but because of a failure to integrate it into output generation. Across architectures, uncerta…

cs.LG2025

What are you sinking? A geometric approach on attention sink

Valeria Ruscio, Umberto Nanni, Fabrizio Silvestri

Attention sink (AS) is a consistent pattern in transformer attention maps where certain tokens (often special tokens or positional anchors) disproportionately attract attention fro…

cs.LG2025

Beyond Position: the emergence of wavelet-like properties in Transformers

Valeria Ruscio, Umberto Nanni, Fabrizio Silvestri

This paper studies how Transformer models with Rotary Position Embeddings (RoPE) develop emergent, wavelet-like properties that compensate for the positional encoding's theoretical…