Page 236 - J. C. Turner "History and Science of Knots"

A History of Topological Knot Theory 227

encountered when traversing clockwise the crossing:
1 -1
Ri = C1zC2z C3iC4t = 1.

In case the crossing includes the unbounded region, the specific gen-
erator's place is taken to be unity. Thus a three-generator relation is
obtained.

3. The collection of n generators, and n relations, as written below, is a
presentation of the knot group.

k = C1,...,Cin
G
^R1= R2=...= Rn =1
In order to provide an example, we shall apply the algorithm to the right-
handed version of the Trefoil Knot, illustrated below.

The diagram gives rise to the following three relations. Note that we have
omitted the identity 1 in each, as we may.

ClC2C: 1 = 1
C1C31C4 =1
C2 C4 C3 1 = 1