Olgo Kharlampovich, I. G. Lysënok, Alexei G. Myasnikov, Nicholas W. M. Touikan. The Solvability Problem for Quadratic Equations over Free Groups is NP-Complete. Theory Comput. Syst., 47(1):250-258, 2010. [doi]
@article{KharlampovichLMT10,
title = {The Solvability Problem for Quadratic Equations over Free Groups is NP-Complete},
author = {Olgo Kharlampovich and I. G. Lysënok and Alexei G. Myasnikov and Nicholas W. M. Touikan},
year = {2010},
doi = {10.1007/s00224-008-9153-7},
url = {http://dx.doi.org/10.1007/s00224-008-9153-7},
tags = {completeness},
researchr = {https://researchr.org/publication/KharlampovichLMT10},
cites = {0},
citedby = {0},
journal = {Theory Comput. Syst.},
volume = {47},
number = {1},
pages = {250-258},
}