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9:23 AM
The tag was created again.
Q: Constructing a basis for a matroid with a circuit in it.

EmptymindHere is the question I am trying to solve (Matroid Theory, second edition by Martin Oxley, Chapter 1, section 2): Prove that if $C$ is a circuit of a matroid $M$ and $e \in C,$ then $M$ has a basis $B$ such that $C = C(e, B).$ My thoughts: My idea for solving this question is that, given a circui...

This was the first instance:
This tag graphic-matroids is not a currently extant tag on the site, and it is generally considered bad form to create a new tag without consulting the community, first. New tags should be proposed in the tag management thread. For further discussion, chat.stackexchange.com/rooms/3740/tagging . — Xander Henderson ♦ Sep 6 at 14:02
9:43 AM
Q: Proving the uncountability of sets for the Entrance Exam Problem

SrijanI am working on entrance exam problem, wherein I aim to demonstrate that the following sets constitute uncountable sets. (A) The set of all $2\times 2$ real matrices with rational eigenvalues. (B) The set of all real matrices whose row echelon form has rational entries My attempt: Set A is unco...

Q: $\sin(x)$ meets Rotating Plane

NickA forward moving sine wave passes through a uniformly rotating plane orthogonal to it, what will the resulting image on the plane look like?

Spirograph is a geometric drawing device that produces mathematical roulette curves of the variety technically known as hypotrochoids and epitrochoids. The well-known toy version was developed by British engineer Denys Fisher and first sold in 1965. The name has been a registered trademark of Hasbro Inc. since 1998 following purchase of the company that had acquired the Denys Fisher company. The Spirograph brand was relaunched worldwide in 2013, with its original product configurations, by Kahootz Toys. == History == In 1827, Greek-born English architect and engineer Peter Hubert Desvign...
4 hours later…
2:12 PM
Q: Proving that $U_{2,n}$ is not regular

EmptymindHere is the question I am trying to solve part (c) in it: $(a)$ Prove that $U_{2,4}$ is representable over a field $\mathbb F$ if anf only if $|\mathbb F| \geq 3.$ $(b)$ For $n \geq 2,$ generalize $(a)$ by finding necessary and sufficient conditions for $U_{2,n}$ to be $\mathbb {F}$-representable...


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