Links to blog post: Exploring the World of Graphs: Planar Graphs, Euler’s Rule, and Digraphs.

Exploring the World of Graphs: Planar Graphs, Euler’s Rule, and Digraphs

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Have you ever wondered how your GPS navigates you through the city or how your internet data travels from one point to another? The answer lies in the fascinating world of graphs in mathematics. Specifically, areas of planar graphs, digraphs and Euler’s rule. Don’t confuse these with bar graphs or pie charts; in mathematical terms, a graph is a set of objects called points or vertices, connected by links known as edges or arcs. These graphs serve as invisible highways guiding everything from your daily commute to your online activities.

Understanding Planar Graphs:

Imagine a flat plane and consider how different points on it can connect without any lines crossing. This leads us to planar graphs. These are drawn on a flat surface, such as paper, without any lines crossing. For example, if you have four friends who need to be connected to each other. A planar graph lets you to draw these connections without any lines crossing.

Exploring Euler’s Rule:

Named after the Swiss mathematician Leonhard Euler, Euler’s rule is a formula that relates the number of vertices, edges, and faces of a planar graph. It is handy in Geometry. Vertices are points where lines meet, whereas edges are the lines themselves. Additionally, faces are the spaces enclosed by these edges. For instance, a cube has eight vertices, twelve edges, and six faces. Euler’s rule states that for any planar graph, the number of vertices minus the number of edges plus the number of faces equals two.

Navigating Directed Graphs (Digraphs) and Networks:

What if connections between points have specific directions? This is where directed graphs, or digraphs, come into play. In a digraph, each edge has an assigned direction, represented by an arrow. This is useful for scenarios like one-way streets in a city. Networks, on the other hand, are digraphs used to represent real-world systems like the internet. Each device is a vertex, and the connections between them (edges) show the flow of data.

Recapping the Journey:

In summary, we’ve explored the basics of planar graphs, delved into Euler’s rule and its applications, and navigated through directed graphs and networks. Mathematics is not just about numbers, it’s also about connections and patterns that help us make sense of our interconnected world.

By understanding these concepts, we gain insights into how systems function, from city traffic to digital networks. So next time you use your GPS or browse the web, remember the underlying mathematics that make it all possible.


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