Explore a thought-provoking lecture on the determinacy strength of Gale-Stewart games from a Reverse Mathematics perspective. Delve into recent discoveries of collapse phenomena in the determinacy hierarchy over boolean combinations of Fσ sets, contrasting with the strictness of alternation hierarchy in μ-calculus. Gain insights into this interdisciplinary field connecting logic, games, and computation as the speaker examines the axioms necessary for proving theorems in this domain. Discover how this research sheds new light on the foundational aspects of lower-level Borel games and their implications for mathematical logic and theoretical computer science.