Here, I compile some (short) notes from previous presentations. There are no new results here (and properly acknowledged so), but perhaps the organization contains sprinkles of originality. While I tried to be careful when crafting the notes, they are inevitably plagued by typoes, flipped inequalities, and similar routine but (potentially) crucial mistakes. Please consume with care, and I wish the big picture and intuition are not smudged by these microscopic imperfections.