PLink Editor Reidemeister Edition
PLink is a full featured graphical editor for knot and link projections, using the cross-platform GUI toolkit Tk. The primary focus is on
piecewise-linear link projections, but it also supports a "smooth mode" and can export images in PostScript, PDF, SVG, and TikZ formats. See
the PLink home page for complete details.
This is a pure Python module and you can install it via pip. See the original documentation for
more. You can browse the original source code here.
In this edition PLink includes functions allowing for the use of Reidemeister moves.
Installation
Use the package manager pip to install plink in terminal.
(Mac users must have version > 10.14.6 for the application to work.)
python -m pip install --index-url https://test.pypi.org/simple/ --no-deps plink-knot-reu
Usage
Type the following into terminal to open the app:
python -m plink.app
Modes
The program starts in default mode, but the user can toggle between any of the five other mode as follows:
R1: Press 1 to activate R1 mode. Click a crossing, and if it is possible to perform
Reidemeister 1 on the crossing, PLink will do so.
R2: Press 2 to activate R2 mode. Click two crossings involving the same links, and if it is
possible to perform Reidemeister 2 on the crossings, PLink will do so.
R3: Press 3 to activate R3 mode. This allows a "global" Reidemiester 3 move. Click two
vertices of the same link, and if the arc between them is either over or under all other arcs, PLink
will delete the selected arc and allow the user to redraw the arc as desired.
U: Press u to activate under mode. This will cause all arrows drawn to go under if it
encounters any new crossings. Can be used during R3 mode.
V: Press v to activate vertex mode. This will allow the user to create new vertices on an
arrow when clicking on a segment of an existing arrow. Though imperfect, this mode will also forbid
the user from creating new crossings or removing them when moving a vertex. This is helpful when we
want to modify the diagram without changing the isotopy class of the link.
Note: simply press the same key again to return to the default mode.
License
Original Licensing: Copyright 2008-present by Marc Culler, Nathan Dunfield, and others.
Reidemeister Edition: Developed by Eric Frankel and Tyler Shibata under the
direction of Ciprian Manolescu and Lisa Piccirillo, available for download here.
All parts of this package are released under the GNU General Public License, version 2 or
(at your discretion) any later version as published by the Free Software Foundation.
Acknowledgements: The development of the original program was partially supported by the US National Science Foundation under grants
DMS0608567, DMS0504975, DMS0204142, and others.
The development of the Reidemeister edition was supported by an undergraduate research stipend provided by Stanford Department of Mathematics.