Blogs about: Set Theory
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Guessing the result of infinitely many coin tosses
I’ve stolen the title of a very interesting post by Andrew Bacon over at Possibly Philosophy. He considers a situation where there will be infinitely many coin flips occurring between noon and … more →
Antimeta
Idempotent Law:
Biswajit wrote 7 hours ago: Law 1: Proof: Let ‘a’ be any element of set . Then, Therefore, …..(1) Again let … more →
Associative Laws:
Biswajit wrote 1 day ago: Law 1: Proof: Let ‘a’ be any element of the set . Then, Therefore, ….(1) Similar … more →
Commutative Laws:
Biswajit wrote 2 days ago: Law 1: Proof: Let ‘a’ be any element of the set . Then, …..(1) Similarly, we can … more →
Halmos 3.5, page 18
Matt wrote 2 days ago: Exercise 1 Let be a disjoint sequence. Show that . Proof: There are two things to show: first, th … more →
Halmos 3.4, page 18
Matt wrote 2 days ago: Exercise 1 Let and be sets. Define the sequence by Show that Proof: Let . Then … more →
Halmos 3.3, page 18
Matt wrote 2 days ago: Theorem 1 The , , and limit (if it exists) are unaltered if a finite number of the terms of the seq … more →
Counting to Infinity (Part II)
Cap Khoury wrote 3 days ago: In the previous article in the series, we looked at what it means for a set to be infinite. We mostl … more →
The truth and set theory: more on Mr. McNamara
— 3 comments
john wrote 1 week ago: Robert S. McNamara struggled with his own humanity in the face of all he had done. His faith in st … more →
Halmos 3.2, page 18
Matt wrote 1 week ago: Definition 1 Let be a sequence of sets. The limit superior of the sets is defined to be The limi … more →
Halmos 3.1, page 18
Matt wrote 1 week ago: I’m not sure if the following result can be restated in terms of our previous results, but I h … more →
Halmos §3, pages 16-18, miscellaneous proofs
Matt wrote 1 week ago: Theorem 1 If is monotone then exists. Moreover, if is increasing then and if is decreasing the … more →
Halmos 2.5, page 15
Matt wrote 2 weeks ago: Exercise 1 (Halmos 2.5) Do the identities and have generalizations to finite, countably infinite, … more →
Halmos 2.4, page 15
Matt wrote 2 weeks ago: Exercise 1 (Halmos 2.4) Note that for all and for all . Show that if and only if for all … more →
Puzzlement about Kripke's proof of the fixed points
jnne wrote 3 weeks ago: I was about to check Field’s remark in the beginning of his chapter 16 that from the Generaliz … more →
Halmos 2.2, page 15
Matt wrote 3 weeks ago: Theorem 1 Let , , and be subsets of . Then (distributivity) (distributivity) Proof: Bo … more →
Halmos 2.1, page 15
Matt wrote 3 weeks ago: Theorem 1 Let , , and be subsets of . Then (commutativity) (commutativity) (associativit … more →
Halmos 1.1, page 11
Matt wrote 3 weeks ago: Consider the partial order on , for some set . Show that is reflexive and transitive. Show that it … more →
The Logic of Local Attractions
— 2 comments
kc wrote 3 weeks ago: On a weekend trip to Riga, the capital of Latvia, my husband posed an amusing question. ‘Why, … more →
Spinoza, Infinite Substance, and Kabbalah Influence
— 5 comments
kvond wrote 3 weeks ago: Math Unto Infinities of Different Sizes and Badiou I’ve been looking into the status of mathe … more →
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An 
Medley
