StefanH

### Questions (764)

 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 9 Categorial definition of subsets

### Reputation (8,203)

 +20 Bounding the number of certain (translation) subsets in $\mathbb N \times \mathbb N$ with respect to given subsets +5 Construction of the lamplighter group as wreath product +5 Arrange points such that translates of orthants separate subsets of them +5 Bounded function on compact interval that is not Lebesgue integrable

 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 (277)

 44 abstract-algebra × 436 20 finite-groups × 233 42 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 8,203 rep 62467 Theoretical Computer Science 1,008 rep 716 Computer Science 805 rep 414 Music: Practice & Theory 697 rep 1618 MathOverflow 373 rep 110