Igor Moiseev

Welcome to my blog.

I’m Igor, an applied mathematician. I write here about geometry, optimal control, formal proofs, machine learning and software engineering, mostly as research series with their equations, figures and code.

Astrophysics 35 min

Grow your own spiral galaxy

$m\approx\dfrac{\kappa^2R}{2\pi G\Sigma X},\quad X\approx2$

A live N-body disc in your browser: light discs, massive discs, bars, tidal encounters and the winding problem

Mathematics 54 min

The Shortest Path When You Cannot Move Sideways

$\dot q=u_1X_1+u_2X_2,\quad X_1=\cos\theta\,\partial_x+\sin\theta\,\partial_y$

An interactive guide to the geometry of motion in the plane: from a simple constraint to the pendulum, competing routes, and the complete shortest-path solution.

Geodesics on SE(2)Part 1 of 1 28 min

Beyond the Shortest Path: Geodesics on SE(2)

$\operatorname{sn}^2(\psi+p)=r(p)$

One research program, three questions: when a path loses local optimality, where nearby paths focus, and how many paths reach the same position and heading. Follow the pendulum, explore the conjugate locus, and count the inverse images.