# CSCI 0220

## Discrete Structures and Probability

CSCI 0220 meets Mondays, Wednesdays, and Fridays from 1:00 - 1:50 pm.

I don't know about you, but we're feeling 22! This class gives you the tools to explore interesting questions and convince yourself and others of their answers. You'll be introduced to new worlds of ideas and ways of thinking. We'll learn about Set Theory, Logic, Number Theory, Combinatorics, Graph Theory, and Probability. If these topics sound unfamiliar, not to fear: you're in exactly the right place! This course assumes no prior experience with these topics.

# Assignments

## Homework

All times listed are in EDT. Homework assignments are released on Tuesday and due at 11:59 PM on Mondays.

Homework | TeX | Released | Due | Solutions |
---|---|---|---|---|

HW0 | - | May 13 | May 17 | - |

HW1 | HW1 TeX | May 18 | May 24 | HW1 Solutions |

HW2 | HW2 TeX | May 25 | May 31 | HW2 Solutions |

HW3 | HW3 TeX | June 1 | June 7 | HW3 Solutions |

HW4 | HW4 TeX | June 8 | June 14 | HW4 Solutions |

HW5 | HW5 TeX | June 15 | June 21 | HW5 Solutions |

Review Questions | Review TeX | June 24 | - | Review Solutions |

Midterm | Midterm TeX | June 28 at 12:01am | June 29 at 11:59pm | Midterm Solutions |

HW6 | HW6 TeX | June 30 | July 6 | HW6 Solutions |

HW7 | HW7 TeX | July 6 | July 12 | HW7 Solutions |

HW8 | HW8 TeX | July 13 | July 19 | HW8 Solutions |

HW9 | HW9 TeX | July 20 | July 26 | - |

HW10 | - | July 27 | August 2 | - |

Final | - | August 9 | August 10 | - |

## Recitation

Name | Released | Solution |
---|---|---|

Rec1 .pdf, .tex | May 20 | .pdf, .tex |

Rec2 .pdf, .tex | May 27 | .pdf, .tex |

Rec3 .pdf, .tex | June 3 | .pdf, .tex |

Rec4 .pdf, .tex | June 10 | .pdf, .tex |

Rec5 .pdf, .tex | June 17 | .pdf, .tex |

Midterm Review (Optional) .pdf, .tex | June 24 | .pdf, .tex |

Rec6 .pdf, .tex | July 1 | .pdf, .tex |

Rec7 .pdf, .tex | July 8 | .pdf, .tex |

Rec8 .pdf, .tex | July 15 | .pdf, .tex |

Rec9 .pdf, .tex | July 22 | - |

Rec10 | July 29 | - |

# Lectures

# Calendar

## How do hours work?

CS22 hours are collaborative spaces for students to work together on problems, facilitated by TAs. Just hop into the Zoom chat and join the breakout room for whichever problem you want to work on. You can call a TA over for help on Signmeup. See our hours policy documentation for more information.

# Resources

## Course Textbook

Mathematics for Computer Science — Lehman, Leighton, MeyerReading this textbook is not required, though many students in the past have found it helpful in reinforcing what's covered in lecture!

## Course Documentation

## Important Links

## Homework Resources

For many of you, this is your first time writing proofs, and even for those who have written proofs
before, what we consider a good proof in CS22 likely differs from what made a good proof wherever
you
were
writing them before! Check out the proof virtues document below to acquaint yourself with what we
consider a good
proof in CS22. ** Your proofs will be graded with respect to this document **, so be sure to read
it
carefully, and come to hours with any questions.

## Math Resources

## Sample Proofs

- Bidirectional
- Bijective Proof Sketch
- More Bijective Proof Sketches
- Bijective Strategies
- Cases
- Contradiction
- Contraposition
- Counterexample
- Induction
- More Induction
- Probability
- Set Equivalence
- Strong Induction

## LaTeX Resources

LaTeX (pronounced *la-tek*) is a program that you will be using to make your homework
solutions
look beautiful. The sample proofs above were written in LaTeX to give you an idea of what documents
written
in LaTeX look like. LaTeX allows you to incorporate mathematical notation into your proofs, and
because
this class involves a healthy dose of mathematical notation, LaTeX is going to be very useful! Using
LaTeX is
required after the 2nd homework.

We don't expect you've ever done this whole LaTeX business before, and that's why we're giving you
some
time to learn it! To get started, we recommend creating an account on
Overleaf, an online program for writing and compiling LaTeX.
After you do that, here are some links to check out:
**
Honestly, please use Overleaf.
It's so much easier than installing anything on your computer. Trust me.
**

- CS22 LaTeX Cheat Sheet (start here!)
- A Not So Short Introduction to LaTeX
- LaTeX Symbols Guide
- Art of Problem Solving: LaTeX
- LaTeX Intro Wikibook
- LaTeX on Brown CS Systems

In general, a really good resource for learning LaTeX is the web. When you have a question, google it, and you'll likely find someone who had the very same question!

Below is a template you can use as a starting point for your homeworks.

If you'd like to download LaTeX on your computer, here are some resources to do that:

If you're using LaTeX and you just don't know what the code for some symbol is, here is a helpful list to start:

Alternatively, this is a neat site which will return the LaTeX code based on handwritten input (although searching your question on the web is likely more efficient):

# Staff

## Michael Littman

Professor | mlittman

I study AI and machine learning and how they might help people more.

๐

## Kyran Flynn

HTA | kflynn6

he/him/his

Hi! I'm a junior studying apma-cs โ tell me how you like your hours

๐ง

## Morley Hawriluk

HTA | mhawrilu

he/him/his

After choosing Brown, didnโt think youโd end up in summer school, did ya?

๐

## Will Yang

HTA | wyang29

he/him/his

Hi there! I'm currently most likely staring at Robinhoood, running down the bike path, or eating on a zoom call.

๐คค

## Ben Fiske

UTA | bfiske1

## Calder Ruhl Hansen

UTA | chansen6

he/him/his

Hi! Iโm a junior from the SF Bay Area. I like designing fonts, learning about space (of course), and making math-related art.

๐

## Ashley Chung

UTA | hchung21

she/her/hers

Howdy! I'm a junior from Connecticut and Seoul, South Korea. I love drawing, playing Tetris, and watching anime. My favorite 22 topics are Number Theory and Sets :)

๐ฅบ

## Jiahua Chen

UTA | jchen345

he/him/his

Hey! I'm from Hong Kong & Shanghai. Talk to me about photography, number theory or cryptography! And yes Pluto is a planet.

๐ฅฐ

## Joanna Tasmin

UTA | jtasmin

she/her/hers

Hi! I'm from Jakarta/Singapore and I study mathsy stuff - I like taking terrible film pictures and graph theory.

๐คก

## Ken Kawamura

UTA | kkawamu1

he/him/his

This is the third time to TA this course!

"ใใใ*'``ใป*ใ ใใใ |ใใใ `*ใ ใใ,ใโฉใใใใ* +ใ (ยดโ๏ฝ ) *ใ+ใ `*ใ ใฝใใใค *ใ* ใ `ใป+ใ*ใป'โ+ใ ใ โใใโช~ใ*ใ ใใ `ใป+ใ*ใป"

## Mary Lou

UTA | mlou2

she/her/hers

Hello! I'm a rising senior studying Biology and CS. I love swimming, baking, and binge-watching dramas with friends.

๐ฅ

## Nick Young

UTA | nyoung10

he/him/his

Hi! I'm from Vancouver, Canada and I love lasagna!

๐

## Claire Chung

UTA | schung25

she/her/hers

## Walter Zhang

UTA | xzhan180

he/his/him

I'm (technically) a junior studying APMA-CS but I also like history, geography, and learning in general!

๐ฟ

## Daniel Ghebreyesus

UTA | dghebrey

he/his/him

Hey! I'm a rising junior from the greater Seattle area studying CS. I enjoy solving crosswords and watching the NBA with friends.

๐ฅณ

## Alyssa Cong

STA | acong3

she/her/hers

hi! i'm a freshman from maryland, and i love my cat (her name is winter, and i am allergic to her. it's fine. allergy meds go a looong way)

๐ค

## Raymond Dai

STA | rdai4

he/him/his

ยฏ\_(ใ)_/ยฏ