Hallucination
A fluent, confident, and false output — the model's normal behaviour applied to something it does not know.
Not a malfunction. A language model is trained to produce likely continuations, and a plausible-sounding citation is a likely continuation whether or not the paper exists. Nothing in the objective distinguishes true from likely, which is why the fix is grounding and verification rather than better prompting.
Where this comes up
Articles that define hallucination in context.
What a transformer is actually doing when it "reads"
Attention, explained through a single nine-token sentence: what the weights mean, why the upper triangle of the matrix is empty, and what that mask has to do with the model's failure modes.
What is Artificial Intelligence?
AI, machine learning, deep learning and generative models are nested, not synonymous. Here is what distinguishes each layer, and which one people now mean when they say AI.