# Online Undergraduate Research Seminar – Jason Metcalfe (UNC) and Marvin Koonce

## November 19 @ 3:30 pm - 4:30 pm

**The sharp lifespan for a multiple speed system of wave equations**

**Abstract.** Ohta examined a system of multiple speed wave equations with small initial data and demonstrated a finite time blowup. We show, in the radial case, that the same system exists almost globally and that the same lifespan is a lower bound. To do this, we use variants of the integrated local energy estimate, the Morawetz estimate that results from using the scaling vector field as a multiplier, and mixed-speed ghost weights.