who is the chess champion of the world
World Chess Championship Current world champion Magnus Carlsen won the World Chess Championship 2013 against Viswanathan Anand and successfully defended his title against Anand in the World Chess Championship 2014 and against Sergey Karjakin in the World Chess Championship 2016.[1]
Marcus Álvarez
Alonso Álvarez de Pineda
1 + 2 + 3 + 4 + ⋯ which increases without bound as n goes to infinity. Because the sequence of partial sums fails to converge to a finite limit, the series does not have a sum.