Central neurocytoma (CN) is a rare and elusive tumor. The relationship between clinical outcome, tumor nature, treatment of CN remains controversial. There were eight patients in our hospital from 2014 to 2021, the prevalence accounted for 0.36% brain tumors. All them underwent surgical removal, two combined with adjuvant radiotherapy (RT). We found that four without complications had small tum...

In 1964, John Stallings established an important relationship between the low-dimensional homology of a group and its lower central series. We establish a similar relationship between the low-dimensional homology of a group and its derived series. We also define a solvable completion of a group that is analogous to the Malcev completion, with the role of the lower central series replaced by the...