When talking about two partitions $\lambda$ and $\mu$, what does the operation $$\lambda/\mu$$ mean? When Macdonald introduces partitions in the first chapter of "Symmetric functions and Hall polynomials", he defines addition, subtraction and multiplication of partitions - but no division. Nevertheless, he uses notation $\lambda/\mu$ later in the book. Any hint?
EDIT:
user254665 seems to suggest that $\lambda/\mu$ is basically the intersection of the two partitions in all of their elements. I.e. this would imply the following example
But I don't quite understand what \ $\{\phi\}$ is supposed to mean.
The symbol $\lambda / \mu$ is the standard notation for a skew shape.
The shape of a partition can be thought of as a geometrical arrangement of boxes (I use o's here). For example, $\lambda = (5,3,2,1)$ is
Now if $\lambda$ and $\mu$ are 2 partitions such that $\mu_i \le \lambda_i$ for all $i$, then $\lambda/\mu$ is a skew shape, obtained by removing the shape $\mu$ from the shape $\lambda$. For example, if $\lambda$ is as above, and $\mu = (4,2,1)$, then $\lambda/\mu$ is the following, where the dots denote removed boxes that are not part of the shape.