← Back to context

Comment by anon291

12 hours ago

It's not contradictory at all. The dfa at each step of the turing machine model is also o(1).

Of course it is. You’re conflating a turing machine with a transformer. Transformers don’t have a local read/write head. The [self] attention is over the whole context, which makes each step O(N) at best (with caching) and O(N^2) w/o.

  • of course it has a read write head. In fact it has N read / write heads equal to the size of the context since each latent state is updated with the results of the cross attention mechanism at each step.

    Alternatively, you can view the '<unknown>' token that is dynamically driven to the embedding of the output token to be the write head. Either way, the simple truth is that you can train a transformer system (i.e., an iteratively applied transformer) to simulate an arbitrary turing machine.