# Day: July 3, 2020

# article: Spaces with Fragmentable Open Sets

Here’s the link.

keywords:

[Mathematics]

[General Topology]

[research result]

[regular topological spaces]

[a metric related to the topology]

# video: How to contact a seller about an order on Amazon

# humorous passage on the divergence of the harmonic series

humorous passage on the divergence of the harmonic series

Here’s the link.

# OBSERVATION (unexported details)

Details not exported become parasites, host-destroying parasites.

keywords:

[life]

[General Systems Theory]

# mathematical word problems involving two people working together

This is also known as ‘the cistern problem’ (two pipes filling a cistern at different rates…).

Here is the link to a discussion of it.

(The discussion contains confusing wording of the solution, but if you read the entire passage you get the correct statement of the solution. The solution is ‘half the harmonic mean of the times’.)

# reference work: Etymological and Historical Dictionary of Mathematics

# GeoGebra

“GeoGebra is an interactive geometry, algebra, statistics and calculus application, intended for learning and teaching mathematics and science from primary school to university level.”

(“with the help of open-source developers and translators all over the world”)

Here is the link to the Wikipedia article on this topic.

keywords:

[Mathematics]

[education]

[instruction]

[training]

[learning]

[study]

[educators]

[interactive]

[interactivity]

[dynamic mathematics software]

# book: A Man Left Albuquerque Heading East

(Word Problems as Genre in Mathematics Education)

Here’s the link to the purchase option on Amazon.