“…We will look at various methods of calibration by initial segment complexity such as those introduced by Solovay [89], Downey, Hirschfeldt, and Nies [26], Downey, Hirschfeldt, and LaForte [23], Downey [16], as well as other methods such as lowness notions of Kučera and Terwijn [47], Terwijn and Zambella [97], Nies [75], [76], Downey, Griffiths and Reid [21], and methods such as higher level randomness notions going back to the work of Kurtz [50], Kautz [38], and Solovay [89], and other calibrations of randomness based on changing definitions along the lines of Schnorr, computable, s-randomness, etc. Particularly fascinating is the recent work on lowness, which began with Downey, Hirschfeldt, Nies and Stephan, and developed in a series of deep papers by Nies [75], [76] and his co-authors.…”