Explore a lecture on "Interacting QFT on causal sets" presented by Emma Albertini at the International Centre for Theoretical Sciences. This 18-minute talk is part of the "Positive Geometry in Scattering Amplitudes and Cosmological Correlators" program, which brings together experts from mathematical aspects of scattering amplitudes and cosmology. Discover how recent advances in perturbative on-shell scattering amplitudes—including unitarity methods, recursion relations, worldsheet models, bootstrap methods, and connections to positive geometry—are pushing toward a reformulation of the perturbative S-matrix using new principles. Learn how these structures relate to cosmological correlators that capture the physics of our Universe, bridging two seemingly different fields of theoretical physics.