Lecture 03 - Network models Flashcards
Networks
What is another name for a network?
A graph
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What does a network consist of?
Nodes/vertices and edges
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What is a neighbour?
If nodes A and B are connected with an edge, they are neighbours.
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What are the two most common ways to represent networks in a computer?
- Adjacency matrix
- Adjacency list
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What is an adjacency matrix?
A matrix of m * m elements which shows how each node is connected to all other nodes.
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What is an adjacency list?
A dictionary mapping nodes to a list of which other nodes they’re connected to. Python annotation: dict[str, list[str]]
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What is this?
An adjacency matrix
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What is this?
An adjacency list
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What is the degree of a node?
The number of edges connected to it.
For directed nodes, there’s a difference between “indegree” and “outdegree” as well
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What’s the typical way of writing the node’s degree?
deg(i), with i being the i-th node.
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What is a walk?
A list of edges that are sequentially connected to form a continuous route in a network.
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What is a trail?
A walk that doesn’t go through any edge more than once.
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What is a path?
A walk that doesn’t go through any node more than once.
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What is a cycle?
A walk that starts and ends at the same node, without going through any node more than once.
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What is this a description of?
“A list of edges that are sequentially connected to form a continuous route in a network.”
A walk
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What is this a description of?
“A walk that doesn’t go through any edge more than once.”
A trail
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What is this a description of?
“A walk that doesn’t go through any node more than once.”
A path
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What is this a description of?
“A walk that starts and ends at the same node, without going through any node more than once.”
A cycle
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What is a subgraph?
A part of the graph.
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What is a connected graph?
A graph in which a path exists between any pair of nodes.
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What is a connected component?
A subgraph of a graph that is connected within itself, but not to the rest of the graph.
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What is this a description of?
“A graph in which a path exists between any pair of nodes.”
A connected graph
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What is the name of a subgraph that is connected within itself, but not to the rest of the graph.
A connected component
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What is this a description of?
“A part of the graph.”
A subgraph
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What is a complete graph?
A graph in which any pair of nodes are connected
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What is a Regular graph?
A graph in which all nodes have the same degree. Every complete graph is regular.
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What is a Bipartite (n-partite) graph ?
A graph whose nodes can be divided into two (or n) groups so that no edge connects nodes between the groups. The groups can be connected within themselves.
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What is a Tree graph?
A graph in which there is no cycle. A graph made of multiple trees is called a forest graph. Every tree or forest graph is bipartite.
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What is a Planar graph?
A graph that can be graphically drawn in a two-dimensional plane with no edge crossings. Every tree or forest graph is planar.
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What is this an example of?
“A graph in which any pair of nodes are connected”
Complete graph
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What is this an example of?
“A graph in which all nodes have the same degree.”
Regular graph
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What is this an example of?
“A graph whose nodes can be divided into two (or n) groups so that no edge connects nodes within each group”
Bipartite (n-partite) graph
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What is this an example of?
“A graph in which there is no cycle.”
Tree graph