We study Dehn surgeries on null-homotopic knots that yield fibred $3$--manifolds when an additional (but natural) homological restriction is imposed. The major tool used is Gabai's theory of sutured manifold decomposition. Such surgeries are negative examples to a question of Michel Boileau. Another result we will prove is about surgeries which reduce the Thurston norm of a fibred manifold.
Harmonic maps M^3 --> S^1 and 2-cycles, realizing the Thurston norm
Link Floer homology and the Thurston norm
On McMullen's and other inequalities for the Thurston norm of link complements
![QR code for arXiv:0712.4387 [math.GT]](http://oss.arxitics.com/images/favicon.svg)