Group presentations corresponding to spines of -manifolds. III

Authors:
R. P. Osborne and R. S. Stevens

Journal:
Trans. Amer. Math. Soc. **234** (1977), 245-251

MSC:
Primary 57A10; Secondary 55A05

DOI:
https://doi.org/10.1090/S0002-9947-1977-0488063-0

MathSciNet review:
0488063

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Abstract | References | Similar Articles | Additional Information

Abstract: Continuing after the previous papers of this series, attention is devoted to RR-systems having two towns (i.e., to compact 3-manifolds with spines corresponding to group presentations having two generators). An interesting kind of symmetry is noted and then used to derive some useful results. Specifically, the following theorems are proved:

Theorem 1. *Let* *be a group presentation corresponding to a spine of a compact orientable* 3-*manifold, and let w be a relator of* *involving just two generators a and b. If w is cyclically reduced, then either*

(a) *w can be ``written backwards"* (*i.e., if* , *then w is a cyclic conjugate of* ), *or*

(b) *w lies in the commutator subgroup of the free group on a and b*.

Theorem 2. (*Loose translation*). *If* *is a group presentation with two generators and if the corresponding* 2-*complex* *is a spine of a closed orientable* 3-*manifold then*, *is a spine of a closed orientable* 3-*manifold if and* (*except for two minor cases*) *only if* *has two relators and among the six allowable types of syllables* (3 *in each generator*), *exactly four occur an odd number of times. Further, each of the two relators can be ``written backwards."*

**[1]**R. S. Stevens,*Classification of*3-*manifolds with certain spines*, Trans. Amer. Math. Soc.**205**(1975), 151-166. MR**50**#11245. MR**0358786 (50:11245)****[2]**R. P. Osborne and R. S. Stevens,*Group presentations corresponding to spines of*3-*manifolds*. I, Amer. J. Math.**96**(1974), 454-471. MR**50**#8529. MR**0356058 (50:8529)****[3]**-,*Group presentations corresponding to spines of*3-*manifolds*. II, Trans. Amer. Math. Soc.**234**(1977), 213-243. MR**0488062 (58:7634a)****[4]**L. P. Neuwirth,*An algorithm for the construction of*3-*manifolds from*2-*complexes*, Proc. Cambridge Philos. Soc.**64**(1968), 603-613. MR**37**#2231. MR**0226642 (37:2231)****[5]**J. S. Birman and H. M. Hilden,*Heegaard splittings of branched coverings of*, Trans. Amer. Math. Soc.**213**(1975), 315-352. MR**0380765 (52:1662)**

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Additional Information

DOI:
https://doi.org/10.1090/S0002-9947-1977-0488063-0

Keywords:
Compact orientable 3-manifold,
spine,
2-complex,
group presentation,
*P*-graph

Article copyright:
© Copyright 1977
American Mathematical Society