Intersections of finitely generated free groups
1985 ◽
Vol 31
(3)
◽
pp. 339-348
◽
A result of Howson is that two finitely generated subgroups U and V of a free group have finitely generated intersection. Hanna Neumann showed further that, if m, n and N are the ranks of U, V and U ∩ V respectively, then N ≤ 2(m−1)(n−1) + 1, and Burns strengthened this, showing that N ≤ 2(m−1)(n−1) − m + 2 (if m ≤ n). This paper presents a new and simple proof of Burns' result. Further, the graph-theoretical ideas used provide still stronger bounds in certain special cases.
2006 ◽
Vol 16
(06)
◽
pp. 1031-1045
◽
Keyword(s):
1971 ◽
Vol 5
(1)
◽
pp. 87-94
◽
Keyword(s):
2012 ◽
Vol 22
(04)
◽
pp. 1250030
Keyword(s):
1999 ◽
Vol 09
(06)
◽
pp. 687-692
◽
2010 ◽
Vol 20
(03)
◽
pp. 343-355
◽
Keyword(s):
Keyword(s):
2001 ◽
Vol 11
(03)
◽
pp. 375-390
Keyword(s):
1972 ◽
Vol 15
(4)
◽
pp. 569-573
◽