Multinomial identities
Channel: Douglas Weathers
Date: 2020-06-20

As generalizations of binomial coefficients, multinomial coefficients inherit a lot of the neat tricks we learned for binomial coefficients (but with much worse notation). 

MISTAKES / subtitles corrected 
Around 2:02 I make the very common mistake of saying that 1+2+1 is 3. That multinomial coefficient is (3 choose 1, 2, 0); both the video and the subtitle correct this.

Meant to be watched before or after reading Chapter 12 of the open source textbook Elementary Discrete Mathematics (https://dweathers.github.io/174/book.html).