Faced with allegations that included bribery and violation of sovereignty, Park was accused of colluding with Choi to secure millions of dollars in bribes from the country's biggest enterprises and allowing Choi, a civilian, to interfere in state affairs. Park had apologized, but denied any wrongdoing.
An aggressive Pyongyang is likely to force Seoul and Tokyo to build nuclear deterrents and thus thwart Beijing's ambitions.
Dr Manjul Bhargava speaks to P Rajendran about winning the Fields Medal, math's biggest global honour.
