2134/17277 Claudia Garetto Claudia Garetto Michael Ruzhansky Michael Ruzhansky A note on weakly hyperbolic equations with analytic principal part Loughborough University 2015 Hyperbolic equations Well-posedness Mathematical Sciences not elsewhere classified 2015-04-15 10:26:34 Journal contribution https://repository.lboro.ac.uk/articles/journal_contribution/A_note_on_weakly_hyperbolic_equations_with_analytic_principal_part/9387440 In this note we show how to include low order terms in the C∞ well-posedness results for weakly hyperbolic equations with analytic time-dependent coefficients. This is achieved by doing a different reduction to a system from the previously used one. We find the Levi conditions such that the C∞ well-posedness continues to hold.