StefanH

### Questions (765)

 19 With this definition of completeness, Gödel's Incompleteness result seems not surprising, so why it was back then? 13 Open Sets in Product Topology. 11 The notation $\prod_{g\in G} g$ for a finite group not well-defined. 10 Show that a semigroup with $aS \cup \{a\} = bS \cup \{b\}$ and $Sa \cup \{a\} = Sb \cup \{b\}$ is a group 10 Simple and intuitive example for Zorns Lemma

### Reputation (8,290)

 +5 Simple and intuitive example for Zorns Lemma +5 Let $X$ and $Y$ be Banach spaces, show that if they are isomorphic, then $X$ is reflexive iff $Y$ is reflexive. +10 How to find the number of anti-symmetric relations? +10 If two elements are in the same orbit, show the stablilizer groups of those elements are conjugate subgroups

 20 Can mathematics get from other sciences what it got from physics? 10 How are simple groups the building blocks? 7 Show that a semigroup with $aS \cup \{a\} = bS \cup \{b\}$ and $Sa \cup \{a\} = Sb \cup \{b\}$ is a group 7 What's the point in being a “skeptical” learner 5 Generalization of $|HK|=\frac{|H||K|}{|H∩K| }$, where $H,K$ are finite subgroups

### Tags (278)

 44 abstract-algebra × 436 20 finite-groups × 233 43 group-theory × 317 20 philosophy × 3 27 soft-question × 3 20 biology 24 book-recommendation × 3 10 regular-language × 15 21 computer-science × 19 10 simple-groups

### Accounts (22)

 Mathematics 8,290 rep 62468 Theoretical Computer Science 958 rep 716 Computer Science 780 rep 414 Music: Practice & Theory 682 rep 1618 MathOverflow 368 rep 110