In light of our discussion of differentials, I want to make a point here that is usually glossed over in most treatments of multivariable calculus. In a very real sense, the sources and targets of our… more →
The Unapologetic MathematicianDan Ma wrote 1 day ago: This is a discussion on several additional conditions that would turn a countably compact space into … more →
Dan Ma wrote 3 days ago: This is a discussion of a basic result about compact spaces, namely the characterization of compactn … more →
Qiaochu Yuan wrote 4 days ago: If it wasn’t clear, in this discussion all rings are assumed commutative. Given a variety like … more →
Dan Ma wrote 4 days ago: It is a classic result in general topology that any compact space with a diagonal is metrizable ([3] … more →
Qiaochu Yuan wrote 5 days ago: Let’s think more about what an abstract theory of unique factorization of primes has to look l … more →
Sunny wrote 6 days ago: There are other important properties of homology, such as excision, but before I delve into those, I … more →
Dan Ma wrote 6 days ago: As the title suggests the spaces are defined using almost disjoint families, in our case, of subsets … more →
arungopalv wrote 1 week ago: The entry point to a SharePoint site is Web Application also known as virtual server in earlier vers … more →
Qiaochu Yuan wrote 1 week ago: An analyst thinks of the ring of polynomials as a useful tool because, on intervals, it is dense in … more →
Sunny wrote 1 week ago: Continuing with properties of singular homology, I will now talk about the invariance of homology un … more →
Andreas Holmstrom wrote 1 week ago: The Events page has been updated again. Some highlights: Copenhagen Topology Conference (Jan 8-10) C … more →
Dan Ma wrote 1 week ago: In a previous post on countable network, it was shown that having a countable network is equivalent … more →
Sunny wrote 1 week ago: Last time, I wrote about singular homology and how it describes topological spaces. Now, I’ll … more →
Dan Ma wrote 1 week ago: In this blog I have already presented two metrization theorems for compact spaces: (1) any compact s … more →
Dan Ma wrote 2 weeks ago: In a previous post, I showed that any compact space with a countable network is metrizable. Another … more →
Dan Ma wrote 2 weeks ago: This is a continuation of the discussion on network. In the previous post, I showed that the network … more →
rosskilgore wrote 2 weeks ago: I’m now jumping to Chapter 6 in Bredon, Geometry and Topology. I want to try to get through a … more →
Dan Ma wrote 2 weeks ago: In the previous post, I discussed the notion of network of a topological space. It was noted that fo … more →
Sunny wrote 2 weeks ago: Informally, homology is supposed to characterize the “holes” in a space. Consider a toru … more →