Recently, Rips produced an example of a double of two free groups which has unsolvable generalized word problem. In this paper, we show that Rips's example fits into a large class of doubles of groups, each member of which contains F2×F2 and therefore has unsolvable generalized word problem and is incoherent. © 2001 Elsevier Science B.V.
Publication Source (Journal or Book title)
Journal of Pure and Applied Algebra
Benakli, N., Dasbach, O., Glasner, Y., & Mangum, B. (2001). A note on doubles of groups. Journal of Pure and Applied Algebra, 156 (2-3), 147-151. https://doi.org/10.1016/S0022-4049(99)00176-0