Richard Penner
Arpie4Math@mathstodon.xyz
<p>SW Engineer, Amateur mathematician (contributed to metamath.org, oeis.org, ...), Legal Tourist (went to Honolulu in 2010 to watch the end of Sancho v. DOE).</p>
Posts
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Post #4384045
New: The Donald J. Trump Revocable Trust v. Capital One, N.A. (25-cv-21596) District Court, S.D. Florida https://www.courtlistener.com/docket/69853458/the-donald-j-trump-revocable-trust-v-capital-one-na/ 2013-2017 DOJ ran "Operation Choke Point" using informal pressure on banks to sever ties ("de-banking") with high-risk-for-fraud businesses like payday lenders, firearm dealers, and pornographic film producers. 2021/01/06 #Trump holds #Jan6 rally 2021/01/20 Trump leaves of...
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Post #4239594
Cantor&#39;s claim is that the infinity of the set real numbers, |β|, is larger than the infinity of the set of counting numbers, |β|. If Cantor is wrong, then there must be a function π:ββΆβ such that the set of real numbers, β, is exactly the same as the image of all natural numbers under function π, π(β) = { π(1), π(2), π(3), ... }. If Cantor is right, then there is no such function, π where π(β) = β. Cantor&#39;s diagonal argument is, at its heart, a proof that a set of size 2^n is s...
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Post #1728984
Take a set, π₯. Is it finite or infinite? Well what definition do you use? β βπ¦ β Οβ π₯ β π¦ ; There is a natural number, π¦, such that you may may map π¦ one-to-one onto the set π₯, enumerating each of its members. So π₯ is finite for the same reason { 1, 2, 3 } is finite. β‘ Β¬ βπ§ β (On β Οβ) π₯ β π§ ; There is no such infinite ordinal, π§, such that you may map π§ one-to-one onto the set π₯. So π₯ is finite because Οβ, the smallest infinite ordinal, cannot be mapped 1-to-1 into it. Do β and β‘ say the sam...
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Post #1728983
Begriffsschrift (1879), is one of the first manuscripts on #SymbolicLogic. As such, it literally invents a new language to describe the subjects the author, #GottlobFrege, wants to introduce. And this notation is very unlike what we see in math before or after this. So I will list some theorems adapted (by me, circa 2020) from #Frege with proper set-theoretical bounds. #SetTheory #Logic #Metamath