rybu's blog

Torus knots with homological longitude

Magnetic field around a conducting Moebius band

Here is another visualization from my course.  We are computing magnetic fields around conductors.  This is part of a demonstration of how (relatively easily) we can compute magnetic fields about fairly arbitrary conductors.  In this case, think of the Moebius band as an interval bundle over a circle.  The electric current is running the the direction of the base circle.  

More elementary stats derived from the VPD page

In the 30-day span of data I downloaded, Saturday appears to be the busiest day for the Victoria police.  

A breakdown of the Victoria Police department "crime types" for all incidents over the past 30 days.

This semester I've been enjoying teaching a course where we use Python.  I've been getting acquainted with its abilities to pull and parse data off the internet, and turn it into useful graphics.  The Victoria Police Department has an incident-report webpage.  I wrote a script to strip the crime data off the webpage and will ask my students to do some basic statistical analysis of the data.  Here is a teaser of what's to come.

Interactive Graphics - Python and Plotly

A completely different graphics engine for Python is called Plotly.   Aside from being a very slick package, the library makes the transition to using your graphics on-line as seamless as possible.  The plot below is an interactive rendering of a parametric surface in R3, a torus knot. You can zoom and rotate with your mouse.  The code to generate the plot was written in Python.

Interactive graphics - Python, SymPy and VisPy

One of my childhood jobs was for an engineering company.  This was back in the days before Matlab or Mathematica.  I would write software for this company (interestingly the company failed and was reincarnated as FlexPipe in 2001, the owners being the previous engineers), to compute numerical integrals to predict the pressure it should take to make their pipe explode, in various configurations.

Why I am no longer a member of the CMS

About a year ago I let my membership to the CMS (Canadian Mathematics Society) lapse.   This has not come easily for me.  It is my hope that Canadian mathematicians have an effective and engaged society.  But I feel the CMS has done too little for Canadian mathematics in relation to its economic burden, and has lost its way.

Cascade Topology Seminar, Spring 2015

The canonical Seifert surface argument

One of the earliest "proper" obstruction-theory arguments in topology goes back to Bruschlinsky, Math. Ann. 109 (1934), stating that the homotopy-classes of maps from a space to the circle are in one-to-one correspondence with the 1-dimensional cohomology of the space. 

[X,S1] = H1(X)

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