Crossing (English)
Search for " Crossing " in NRICH | PLUS | maths.org | Google
Definition (keystage 3)
Knots are classified by the number of times the 'string' crosses itself when the knot is projected onto a plane. For any knot this number of crossings has a smallest possible value, which is called the number of crossings.
There exists one prime knot with 3 crossings,
one with 4 crossings,
2 with 5 crossings,
3 with 6 crossings,
7 with 7 crossings,
21 with 8 crossings,
49 with 9 crossings,
165 with 10 crossings.
There exists one prime knot with 3 crossings,
one with 4 crossings,
2 with 5 crossings,
3 with 6 crossings,
7 with 7 crossings,
21 with 8 crossings,
49 with 9 crossings,
165 with 10 crossings.
Relations
- broader:
- (en) Attribute taking discrete values
- (en) Integer
- references:
- (en) Knot
Funded by: EU Socrates Minerva, HeyMath!, Cambridge University Press