$C$-dense (mixing) Axiom A flows speed of mixing asymptotic expression for the number of periodic orbits is $\varphi_1$ intrinsically ergodic? direct proof of mixing of measures analogue of $h(f) \geq \log |\lambda| $ understand det$(Id - A) $ as an invariant; relation to $\zeta (0)$ stability of $C$-density for attractors condition on $g$ so that $\Sigma_A (g) $ is analytically or $C^\infty $ embeddable as a basic set. can a closed orbit of an Anosov flow be null homotopic?