"The note is scattered with exercises; solving them, the reader will become a master in co/end-fu (端楔術; literally “the art [of handling] terminal wedges”)"
Apparently to get a PhD in math, I'm gonna need to be able to read a math paper in either French, German, or Russian and translate it. I'm years away from that but I got worried @SubhasisBiswas
I then decided that, since math papers will generally use a limited vocabulary, I'll probably be alright
especially since I know Spanish which is similar to French
The smallest grammar problem is to find a minimal cost grammar $g$ of an input string $s$ over $\Sigma$. Then $g$ expands back to $s$ in an obvious way. For example: $g = \{S \to AA, A \to abc \}$ expands to the the input string $s=abcabc$ and is in fact a smallest grammar for $s$.
Now take a...