Calligraphy

The Chinese character that appears on the left of the logo is a stylized version of 数 which means “to count” (as a verb) or a “number/value/sum” (as a noun). The Chinese word for mathematics is 数学, the art or study of 数. Number theory is rendered 数论, literally the theory of numbers. Now in Chinese, the character 数 when used as a noun, is pronounced in exactly the same way as 树, which is a tree. Note how the stylized character on the PME36 logo has many extra strokes to make it look like a tree and yet is recognisable. Nice!