In the mathematical area of knot theory, the unknotting number of a knot is the minimum number of times the knot must be passed through itself (crossing switch) to untie it. If a knot has unknotting number n {\displaystyle n} , then there exists a diagram of the knot which can be changed to unknot by switching n {\displaystyle n} crossings.
In the mathematical area of knot theory, the unknotting number of a knot is the minimum number of times the knot must be passed through itself (crossing switch) to untie it. If a knot has unknotting number n {\displaystyle n} , then there exists a diagram of the knot which can be changed to unknot by switching n {\displaystyle n} crossings.
Source: Wikipedia "Unknotting number" · CC BY-SA 4.0
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