講座ものの空箱の利用法

The gathered works of mathematics were published. In each book-case three parts were contained. Some book consists of one part，of two parts, of three parts, or of four parts. The best way is to bind these parts into one volume according to the name of the book, but my budget is not enough to do so. Therefore I decid ed to keep each book in one case (if possible) which should have its name on it. Of course those which have more than three parts may be sepatated into two or three cases. This theory is how to think about the metbod of combinating the parts and cases.