curver 0.3.5

For calculations in the curve complex

Curver is a program for performing calculations in the curve complex. It implements the Bell–Webb algorithm to determine the Nielsen–Thurston type of a mapping class. This algorithm runs in polynomial time but the constants involved currently make this implementation impractical.

Curver officially supports Python 2.7 and 3.4 – 3.7. It also runs on PyPy and Sage.

A taste of curver:

>>> S = curver.load(0, 5)
>>> S('s_0.s_1.s_0') == S('s_1.s_0.s_1')
True
>>> S('s_0.s_1.s_2.s_3').order(), S('s_0.s_1.s_3.s_2').order(), S('s_0.s_1.S_2.S_3').order()
(5, 5, 5)
>>> S('s_0.s_1.s_2.s_3').is_conjugate_to(S('s_0.s_1.s_3.s_2'))
True
>>> S('s_0.s_1.s_2.s_3').is_conjugate_to(S('s_0.s_1.S_2.S_3'))
False

Features

• Solves the word problem for mapping class groups.
• Performs Nielsen–Thurston classification of mapping classes.
• Solves the conjugacy problem for periodic mapping classes.
• Computes the asymptotic translation length of mapping classes on the curve complex.
• Computes geodesics in the curve complex.
• Computes quotient orbifolds and their quotient maps.
• Computes the action of mapping classes on H_1.
• Determines the topological type of multicurves.

External Links

• PyPI
• ReadTheDocs
• GitHub
• Travis
• AppVeyor
• Azure
• Coveralls