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. …

Mar 5, 2011 · It's curious --and unfortunate-- that the symbol for emphasis became the symbol for negation. Granted, ASCII isn't the richest glyph set, and coders needed something, but why …

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. …

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 …

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.

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 …

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 …

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 …

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

Even though there appears to be some confusion as to exactly What are the "whole numbers"?, my question is what is the symbol to represent the set $0, 1, 2, \ldots $.