Aug 4, 2021 · Whenever a problem or question of isomorphism comes up I am clueless as to what they mean. From my understanding an isomorphism is in terms of graph theory where it is the same thing …

Jul 25, 2017 · There is a whole school of notation preferring $\subsetneq$ or even $\subsetneqq$ for proper subsets, since there is also a school of notation using $\subset$ for $\subseteq$. So clarity is …

Mar 5, 2026 · I'm not convinced this is in the range of questions for math.SE. It may be better posed at mathoverflow.

Feb 26, 2026 · There is a different argument but I feel it is not as insightful. Also, heuristically, we should not expect such an argument to exist because sheafification has a left-sided universal property (i.e. …

Nov 8, 2019 · I stuck on something. I am trying to understand what is said in the image I linked above. "A function I from a set Λ onto a set a is said to index the set a by Λ. The set Λ is called the index an...

Jul 10, 2021 · While reading about quadratic equations, I came across Newton's Identity formula which said we can express $\\alpha^n+\\beta^n$ in simpler forms but not given any ...

Suppose I am trying to prove a statement in the form A if and only if B. I know I need to prove that If A, then B If B, then A I know that 1 is equivalent to proving "If not B, then not A". My

Feb 16, 2026 · Maybe you are right. The question seemed too low-level for MO, but it is rather specific. So Ill wait for a couple more days and then cross-post...

edit: Thanks for the help! I spent a while thinking about the problem and trying to determine "how big an object is at 100 feet" but you can't have something be, for example, 4 inches at a distance of 0 feet …

Jul 23, 2025 · Consider the following game. You get to roll a six-sided dice continuously until you roll the same number twice in a row. At this point the games ends, and you are paid the product of all your rolls.