# Applications of LA in Combinatorics

Tutorials for Applications of Linear Algebra in Combinatorics [NDMI028] in winter semester 2022/2023. Tutorials take place on Friday 15:40 at K12, Karlín. I lead the tutorials together with prof. Kratochvíl.

## Course completion requirements

It is required to attend all tutorials and submit solution to home assignments in order to pass the course tutorials. There are two types of homework:

- *-type: Every week, one assignment will be posted and you have two weeks to finish it. To pass the tutorials, you have to submit at least half of the assignments.
- a-type: If you do not attend tutorials, you have to submit homework assignments corresponding to the tutorials.

## HW submission progress

## Homework assignments

Date: | Topic: | Materials: | Deadline: |
---|---|---|---|

7. 10. 2022 | Revision of Linear Algebra | here | 21. 10. 2022 |

14. 10. 2022 | Determinants and Odd/Even cities | here | 28. 10. 2022 |

21. 10. 2022 | Odd cities | here | 4. 11. 2022 |

28. 10. 2022 | National holiday | here | 28. 10. 2022 |

4. 11. 2022 | Mod-q cities | here | 18. 11. 2022 |

11. 11. 2022 | Spectral graph theory I. | here | 25. 11. 2022 |

18. 11. 2022 | Spectral graph theory II. | here | 2. 12. 2022 |

25. 11. 2022 | Spectral graph theory III. | here | 9. 12. 2022 |

## Lectures

The lecture notes are avalaible only in Czech. For materials in English, contact prof. Kratochvil at honza@kam.mff.cuni.cz.

Date: | Topic: | Materials: |
---|---|---|

7. 10. 2022 | Matrix representations of graphs, powers of the adjacency matrix, determinants and spanning trees | here |

14. 10. 2022 | Linear (in)dependece, sizes of special set systems, 2-distances sets | here |

21. 10. 2022 | Orthogonality and orthogonal complements, cycle space of a graph | here |

28. 10. 2022 | National holiday | here |

4. 11. 2022 | Linear forms, dual homomorphisms, Seidel switching | here |

11. 11. 2022 | Spectral graph theory, eigenvalues of graphs, Moore graphs | here |

18. 11. 2022 | Strongly regular graphs, friendship theorem, interlacing of eigenvalues | here |

25. 11. 2022 | Applications of interlacing of eigenvalues | here |