Unit2HOLIDAYREVISEFROEXAMSA+NEEDBYTERM4 Flashcards
Vertex
How many pints there are e.g. a,b,c,d connect to make a graph, so there are 4 points.
Isolated vertex
not connected to nay vertex.
Connected vertex
Has every vertex connected to every other vertex either either directly or indirectly via other vertices.
Adjacency matrix
Mathematical representation of a diagram:
- 0= no direct connection.
- 1’s in diagonal=loop
- column all 0’s= isolated vertex.
Planar graph
Graphs that can be drawn with no overlapping edges. They follow the Euler’s formula: v-e+f=2
Isomorphic graph
- The same graph drawn in a different way.
- Same no of edges and vertices and the corresponding vertices have the same degree and the edges connect the same vertices.
Complete graph
- A network where all vertices are connected directly to all other vertices without parallel edges or loops.
Walks
- Starts at one vertex and follows any route to finish at another vertex.
- You must record the order you visit the edges.
Trails
- A walk with no repeated edges.
Paths
- A walk with no repeated edges or vertices.
Circuit
- A walk with no repeated edges that starts and ends at the same vertex:
IN SUMMARY: - TAKE ANY ROUTE
- RECORD ROUTE
- START AND END AT SAME VERTEX
- NO REAPTED EDGES OR VETRICES
Cycle
- A walk with no repeated edges or vertices that starts and ends at the same vertex.
Eulerian trail
Follows every edge of a graph and will exist if it is:
- It is connected
- It has exactly tow vertices that have an odd degree.
Eulerian circuit
Follows every edge and starts and ends at the same vertex.
- It is connected
- Has vertices of all even degree.
Hamiltonian path
- Visits every vertex of graph once.
- Don’t have to start and end at the same vertex.
- No more than 2 vertices of degree 1.
Hamiltonian cycle
- Visits every vertex of graph.
- Stars and ends at the same vertex.
Subgraph
- A small part of a large graph that has some of the same vertices and edges as the larger one.
Tree
- A connected graph:
- No cycles.
- No loops or edges.
- The number of edges can be calculated using (n-1), where n i the number of vertices.
Spanning tree
- A connected graph:
- No cycles.
- No loops or edges.
- It is found by counting the no. of vertices (n) and removing enough edges so that there are n-1 edges, where n is the no. of edges and they should connect all vertices.
Prims algorithm
A formula for determining the minimum spanning tree of a network.
Bridge
-Is an edge in a connected graph, that if removed will cause the graph to be disconnected.
Disconnected graph
- Are graphs that are not connected.
Euler’s formula is?
- v-e+f=2