Lecture
Notes
Here are some expository type notes on different topics.
Combinatorics
Van der
Waerden's theorem
A Combinatorial proof of Roth theorem
The Balog-Szemeredi theorem
Fourier analysis
A Short proof of Roth' theorem
Weyl's lemma and Sarkozy's theorem
Sums of squares and the Circle Method
Ergodic theory
Ergodic proof of Roth
theorem
Short proof of the poinwise ergodic theorem
Here one can find some expository notes (jointly with Neil Lyall) and
some links on Ramsey
Theory.