The following are exercises from The Four Pillars of Geometry; I’m not sure what they are stating, for example I don’t know what the addition of prime (an apostrophe) to a line means. There are no examples or references. 3.6.5 Show that the reflections in lines $L$, $M$, and $N$ (in that order) have the […]

H.G Wells’ short story The Plattner Story is about a man who somehow ends up being “inverted” from left to right. So his heart has moved from left to right, his brain, and any other asymmetries belonging to him. Then H.G Wells’ goes on a slight metaphysical exposition: There is no way of taking a […]

Artin’s Algebra pages 155 & 156 list the types of symmetry of a plane figure as: Reflective Rotational Translational Glide He then goes on to say “Figures such as wallpaper patterns may have two talk about other figures having combinations of independent” symmetries. EDIT: He says “… having combinations of independent translational symmetries”. See Joriki’s […]

Intereting Posts

Probability mean is less than 5 given that poisson distribution states it is 6
Closed form for $\int_0^e\mathrm{Li}_2(\ln{x})\,dx$?
Irreducible polynomial of $\mathrm{GF}(2^{16})$
When is the sum of divisors a perfect square?
$B$ is a Borel set, implies $f(B)$ is a Borel set.
Is there a number that is palindromal in both base 2 and base 3?
Books that follow axiomatic approach?
Gradient of l2 norm squared
How many circles are needed to cover a rectangle?
Complement of a bounded set $B$ in $\mathbb{R}^{n}$ has exactly one unbounded component.
Bochner Integral vs. Riemann Integral
Countable disjoint union of non-measurable sets
How many pairs of numbers are there so they are the inverse of each other and they have the same decimal part?
How to evaluate the integral $\int_0^\infty \frac{x^{a-1}}{1+bx^a} e^{-x} dx$
Finding the Fourier transform of $f(x) = \frac{a}{\pi} \frac{1}{a^2 + x^2}$ with the residue theorem