The term "Ironic complexity" was coined by Scott Aaronson for the stuff Ryan Williams does in the area of complexity theory. Could anyone tell me what kind of problems and approaches does Ryan Williams work upon? And is there a survey or course on it for self-study?
Here is a quote from Scott Aaronson's survey on the P vs NP question, in which he coined this term:
There is one technique that has had some striking recent successes in proving circuit lower bounds, and that bypasses the natural proofs, relativization, and algebrization barriers. This technique might be called “ironic complexity theory.” It uses the existence of surprising algorithms in one setting to show the nonexistence of algorithms in another setting. It thus reveals a “duality” between upper and lower bounds, and reduces the problem of proving impossibility theorems to the much better-understood task of designing efficient algorithms.
The survey contains some pointers which you might want to look at.