Cowboy bowline so easily pushed back by accident. However, there is no documentation to confirm this claim, and some Dutch knot tyers outright deny it. Another piece of unverified lore is that it is called a winter bowline because the exposed working end on the outside would blow in the wind and prevent it from freezing to the loop on ships in the north Atlantic during winter. (This suggests that the standard bowline would be the summer bowline.) "The Ashley Book of Knots" states that it is "distinctly inferior" to the standard bowline because of its similarity to the left-hand sheet bend.
Arf invariant of a knot if they are related by a finite sequence of pass-moves, which are illustrated below: (no figure right now) Every knot is pass-equivalent to either the unknot or the trefoil; these two knots are not pass-equivalent and additionally, the right- and left-handed trefoils are pass-equivalent. Now we can define the Arf invariant of a knot to be 0 if it is pass-equivalent to the unknot, or 1 if it is pass-equivalent to the trefoil. This definition is equivalent to the one above. Vaughan Jones showed that the Arf invariant can be obtained by taking the partition function of a signed planar