Deep learning is a subtopic within machine learning, which is on topic. Deep learning is just, um, deeper than regular machine learning. Note that we have an active tag, deep-belief-networks, that pertains to deep learning with 89 threads. We have also had tags for [deep-learning] and [deep-rl] that are now mapped to neural-networks and reinforcement-learning. That doesn't mean that those topics became off limits, just that, e.g., deep learning is now nearly synonymous with neural networks and it isn't useful for us to maintain distinct tags from the perspective of organizing the information on the site. I also find 631 questions with "deep" in the title, of which 90% are not closed.
Artificial intelligence is somewhat trickier. We do have an artificial-intelligence tag that hosts 229 threads. However, AI is a broader topic than machine learning, rather than a subset. There are aspects of AI that would not fall within our scope. In addition, there is an artificial intelligence SE site, where such questions (even the broader ones) can be asked and might find a better audience.
