Displaying similar documents to “Nielsen reduction in free groups with operators”

Density of Critical Factorizations

Tero Harju, Dirk Nowotka (2010)

RAIRO - Theoretical Informatics and Applications

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We investigate the density of critical factorizations of infinite sequences of words. The density of critical factorizations of a word is the ratio between the number of positions that permit a critical factorization, and the number of all positions of a word. We give a short proof of the Critical Factorization Theorem and show that the maximal number of noncritical positions of a word between two critical ones is less than the period of that word. Therefore, we consider only...

Parametrized h -cobordism theory

Allen E. Hatcher (1973)

Annales de l'institut Fourier

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This paper gives an expository account of the author’s work on the “second” obstruction to deforming a pseudo-isotopy on a smooth compact manifold to an isotopy. Using earlier results on the “first” obstruction, due independently to J.B. Wagoner and the author, this completes the generalization of J. Cerf’s pseudo-isotopy theorem to the non-simply-connected case.