In 1897 , in prison , he wrote De Profundis , which was published in 1905 , a long letter which discusses his spiritual journey through his trials , forming a dark counterpoint to his earlier philosophy of pleasure .
In prison he wrote De Profundis , a long letter which discusses his spiritual journey through his trials , forming a dark counterpoint to his earlier philosophy of pleasure .
He studied mathematics from 1975 to 1979 in Chemnitz . In 1980 , he went to Rostov on Don to study and earned a PhD there in 1984 .