There are knots whose tunnel numbers go down under connected sum

Morimoto, Kanji

doi:10.1090/S0002-9939-1995-1317043-4

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ISSN 1088-6826(online) ISSN 0002-9939(print)

There are knots whose tunnel numbers go down under connected sum

Author: Kanji Morimoto
Journal: Proc. Amer. Math. Soc. 123 (1995), 3527-3532
MSC: Primary 57M25
MathSciNet review: 1317043
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Abstract: In this paper, we show that there are infinitely many tunnel number two knots K such that the tunnel number of $K\char93 K'$ is equal to two again for any 2-bridge knot .

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