The symbol ≅ is used for isomorphism of objects of a category, and in particular for isomorphism of categories (which are objects of CAT). The symbol ≃ is used for equivalence of categories. …

Jun 25, 2014 · I have started seeing the "∈" symbol in math. What exactly does it mean? I have tried googling it but google takes the symbol out of the search.

Jul 23, 2013 · $\\mathbb Q$ is used to represent rational numbers. $\\mathbb R$ is used to represent reals. Is there a symbol or convention that represents irrationals. Possibly $\\mathbb …

18 $$:=$$ is the commonest symbol to denote "is equal by definition." Note that $$\equiv$$ is used to denote an algebraic identity: this means that the equation is true for all permitted …

Dec 13, 2016 · An unsophisticated question from a neophyte: Given the numbers: $1,2,3,4,5$ What is the symbol for the range of the numbers? i.e. the lowest-highest number in the set. …

In set theory \mid or : is often used but I haven't really seen any logical symbol used for "such that" in other situations. But now that I think of it there is the \ni symbol used as "such that" in …

There is a common thread running through many of the mysteries and hints in the series—the mysterious symbol, (alleged) astronomical symbols, cannibalism, and the sign of the bird and …

I just came across this annotation in my school's maths compendium: The compendium is very brief and doesn't explain what this means.

13 I have found some pretty complete lists (I think) of mathematical symbols here and here, but I don't see a symbol for the word "and" on either list. A person could easily just write the word …

Nobody should be using $\ni$ to mean "such that"; it is used in texts everywhere to mean $\in$ but in the reverse direction. (that's why the LaTeX code is "\ni" after all). I would argue ":" is the …