Skip to main content
7 events
when toggle format what by license comment
Sep 20, 2017 at 20:35 comment added j.c. I may be missing something but the "splicing" one typically does with Bézier curves does not preserve "algebraic curveness" as I understand it. Splicing gives you a curve that is piecewise parametrized by polynomials but the condition of being an algebraic curve is that the curve is globally the solution set to a system of polynomials. See the definitions here en.wikipedia.org/wiki/Algebraic_curve
Sep 20, 2017 at 20:09 comment added David G. Stork Dustin and j.c.: I can parameterize the component trefoil portions in any number of ways. I can also use parameterizations of basis sets, such as Bezier curves (which obey real algebraic equations) to continuously splice the components together, thereby preserving algebraic curveness.
Sep 20, 2017 at 19:25 comment added j.c. @DavidG.Stork Sorry, I don't understand your comment. To be more explicit, let us take as given that the two trefoils that you show can be represented by (say, [parametrized by] and/or [the solution set of]) real algebraic (polynomial) equations (though even this is not obvious to me). How do you ensure that the connected sum that you show (your joining operation) is also represented by real algebraic equations?
Sep 20, 2017 at 18:51 comment added David G. Stork Yes... Simply assign the different crossings (as described) to the projections to see that the resulting knots (or un-knot) preserve real-algebraic curveness.
Sep 20, 2017 at 18:47 comment added Dustin G. Mixon Is it clear that your joining operation preserves real-algebraic-curveness?
Sep 20, 2017 at 18:44 history edited David G. Stork CC BY-SA 3.0
added 129 characters in body
Sep 20, 2017 at 18:35 history answered David G. Stork CC BY-SA 3.0