RT Journal Article T1 Quasiaspherical knots with infinitely many ends A1 Montesinos Amilibia, José María A1 González Acuña, Francisco Javier AB A smooth n-knot K in Sn+2 is said to be quasiaspherical if Hn+1(U)=0, where U is the universal cover of the exterior of K. Let G be the group of K and H the subgroup generated by a meridian. Then (G,H) is said to be unsplittable if G does not have a free product with amalgamation decomposition A∗FB with F finite and H contained in A. The authors prove that K is quasiaspherical if and only if (G,H) is unsplittable. If the group of K has a finite number of ends, then K is quasiaspherical and it was conjectured by the reviewer [J. Pure Appl. Algebra 20 (1981), no. 3, 317–324; MR0604323 (82j:57019)] that the converse was true. The authors give a very nice and useful method of constructing knots in Sn+2 and apply this method to produce counterexamples to the conjecture. PB European Mathematical Society SN 0010-2571 YR 1983 FD 1983 LK https://hdl.handle.net/20.500.14352/64700 UL https://hdl.handle.net/20.500.14352/64700 LA eng NO BIERI, R.,Mayer-Vietoris sequences for HNN-groups and homological duality, Math. Z.143 (1975) 123–130. GONZÁLEZ-ACUÑA, F., andMONTESINOS, J. M.,Ends of knot groups, Annals of Math.108 (1978) 91–96. LOMONACO, S.,The homotopy groups of knots I; how to compute the algebraic 2-type, Pacific J. Math.95 (1981) 349–390.RATCLIFFE, J.,On the ends of higher dimensional knot groups, J. Pure and Appl. Alg.20 (1981) 317–324 STALLINGS, J.,Group theory and three-dimensional manifolds, New Haven and London, Yale University Press (1971).SWAN, R. G.,Groups of cohomological dimension one, Journal of Algebra12 (1969) 585–601. SWARUP, A.,An unknotting criterion, Journal of Pure and Applied Algebra6 (1975) 291–296. WALL, C. T. C.,Pairs of relative cohomological dimension one, Journal of Pure and Applied Algebra1 (1971) 141–154. SERRE, J. P. Arbres, Amalgames, Sl 2, Asterisque46 (1977).DUNWOODY, M. J.,Accessibility and groups of cohomological dimension one, Proc. London Math. Soc.38 (1979), 193–215. NO Comission Asesora del MUI DS Docta Complutense RD 1 may 2024