We open with a simple mathematical puzzle that is easily solved using only elementary reasoning. Imagine a party where some guests are friends while others are unacquainted. Then the following is always true: No matter how many guests there are at the party, there are always two guests with the same number of friends present. … Continue reading Order in the midst of Chaos
Tag: Graph Theory
Topology in the Oval Office
Imagine a room – the Oval Office for example – that has three electrical appliances: • An air-conditioner ( a ) with an American plug socket ( A ), • A boiler ( b ) with a British plug socket ( B ), • A coffee-maker ( c ) with a Continental plug socket ( … Continue reading Topology in the Oval Office
Venn Again’s Awake
We wrote about the basic properties of Venn diagrams in an earlier post. Now we take a deeper look. John Venn, a logician and philosopher, born in Hull, Yorkshire in 1834, introduced the diagrams in a paper in 1880 and in his book Symbolic Logic, published one year later. The diagrams were used long before … Continue reading Venn Again’s Awake
Big Data: the Information Explosion
The world is awash with data. Large data sets have been available for many decades but in recent years their volumes have grown explosively. With mobile devices and internet connections data capture is simple and with powerful computers the analysis of “big data” is feasible [see TM092, or search for “thatsmaths” at irishtimes.com]. But there are … Continue reading Big Data: the Information Explosion
Numbering the Family Tree
The availability of large historical data sets online has spurred interest in genealogy and family history. Anyone who has assembled information knows how important it is to organize it systematically. A simple family tree showing the direct ancestors of Wanda One is shown here: This has just three generations but, as more people are added, … Continue reading Numbering the Family Tree
It’s a Small – Networked – World
Networks are everywhere in the modern world. They may be physical constructs, like the transport system or power grid, or more abstract entities like family trees or the World Wide Web. A network is a collection of nodes linked together, like cities connected by roads or people genetically related to each other. Such a system … Continue reading It’s a Small – Networked – World
ThatsMaths 