Ordinary attention grows more expensive as text grows. compresses the past into a fixed-size memory, but many facts in the same memory overwrite each other. A newer design erases old answers before writing new ones, yet treating erasure and writing as equally important wastes capacity.
Muir analyzes where capacity actually goes: writing matters far more than erasing. It spends fewer parameters on erasure, widens the feed-forward network that stores associations, re-weights old memory rows so they do not dominate, and keeps training stable.
At the largest size tested, Muir lowers perplexity, a prediction-quality measure, by about 2 percent over a strong baseline, and keeps near-perfect retrieval after a million tokens, making long-context models cheaper and more reliable.
