Thread:Argali1/@comment-26453572-20151008025020/@comment-27723099-20151008195852

Every day I have to learn some new symbols. One example of some time ago, the criterium that must be fulfilled for a group to be closed, one of the requirements of an abelian group:

∀ a ∈ G  ∃ b ∈ G : a * b ∈ G

Or something else, something that goes against all intuitive logic for me:


 * &#8407;a ||² = <&#8407;a, &#8407;a> = &#8407;a² (where ||x|| is the euklidian norm and  the euklidian skalar product)

But since it has no numbers in it, it shouldn't be considered as the same as what you are doing in math, right?