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#peano

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ƧƿѦςɛ♏ѦਹѤʞ<p>Provably unprovable? <a href="https://mastodon.social/tags/WTF" class="mention hashtag" rel="tag">#<span>WTF</span></a> :-) <br /><a href="https://www.youtube.com/watch?v=0Le7NgS-wO0" target="_blank" rel="nofollow noopener" translate="no"><span class="invisible">https://www.</span><span class="">youtube.com/watch?v=0Le7NgS-wO0</span><span class="invisible"></span></a><br /><a href="https://mastodon.social/tags/maths" class="mention hashtag" rel="tag">#<span>maths</span></a> <a href="https://mastodon.social/tags/mathematics" class="mention hashtag" rel="tag">#<span>mathematics</span></a> <a href="https://mastodon.social/tags/numbers" class="mention hashtag" rel="tag">#<span>numbers</span></a> <a href="https://mastodon.social/tags/Goodstein" class="mention hashtag" rel="tag">#<span>Goodstein</span></a> <a href="https://mastodon.social/tags/Peano" class="mention hashtag" rel="tag">#<span>Peano</span></a> <a href="https://mastodon.social/tags/G%C3%B6del" class="mention hashtag" rel="tag">#<span>Gödel</span></a> <a href="https://mastodon.social/tags/sequence" class="mention hashtag" rel="tag">#<span>sequence</span></a></p>
Apuntes de ciencia<p>Mi hijo (13) me ha preguntado "Si 1=2, ¿cuánto vale 1+1+1+1?" y yo he aprovechado para hablarle de los axiomas de <a href="https://astrodon.social/tags/Peano" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Peano</span></a> 😋<br>➡️<a href="https://es.wikipedia.org/wiki/Axiomas_de_Peano" rel="nofollow noopener" target="_blank"><span class="invisible">https://</span><span class="ellipsis">es.wikipedia.org/wiki/Axiomas_</span><span class="invisible">de_Peano</span></a></p>
Ian Douglas Scott<p>fn main() {<br> println!("{}", &lt;S&lt;S&lt;S&lt;S&lt;Z&gt;&gt;&gt;&gt; as Nat&gt;::Fact::INT);<br>}</p><p><a href="https://fosstodon.org/tags/peano" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>peano</span></a></p>
SDF.ORG<p>gosper's graph of a space filling function painting successive range points with gradient color <a href="https://mastodon.sdf.org/tags/hack" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>hack</span></a> <a href="https://mastodon.sdf.org/tags/math" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>math</span></a> <a href="https://mastodon.sdf.org/tags/peano" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>peano</span></a> <a href="https://mastodon.sdf.org/tags/lisp" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>lisp</span></a> <a href="https://mastodon.sdf.org/tags/mandlebrot" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>mandlebrot</span></a></p>
xameer<p>So which is more natural? Shapes which we see in nature or the natural numbers, which we need to define them in full? <br>How could <a href="https://ioc.exchange/tags/peano" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>peano</span></a> just assume that 0 is a natural number ? What is a shape with zero sides? Is infinity a natural number too? <br>What tells N from R?</p>
xameer<p>- In <a href="https://ioc.exchange/tags/Peano" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Peano</span></a> arithmetic, second-order arithmetic and related systems, and indeed in most (not necessarily formal) mathematical treatments of the well-ordering principle, the principle is derived from the principle of mathematical induction, which is itself taken as basic</p>
xameer<p>- strengthened finite <a href="https://ioc.exchange/tags/Ramsey" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Ramsey</span></a> theorem, is true, but not provable in Peano arithmetic. This was the first "natural" example of a true statement about the integers that could be stated in the language of arithmetic, but not proved in <a href="https://ioc.exchange/tags/Peano" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Peano</span></a> arithmetic<br><a href="https://ioc.exchange/tags/godel" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>godel</span></a></p>
xameer<p>- Relation algebra algebraizes part of fol consisting of formulas having no atomic formula lying in scope of &gt;3 quantifiers. Enough , for <a href="https://ioc.exchange/tags/Peano" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Peano</span></a> arithmetic , axiomatic set theory <a href="https://ioc.exchange/tags/ZFC" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ZFC</span></a>; hence relation algebra, unlike PFL, is incompletable</p>
xameer<p><a href="https://ioc.exchange/tags/Peano" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Peano</span></a> and Mario Pieri used the expression motion for the congruence of point pairs</p>
xameer<p>Hydra will eventually be killed, regardless of the strategy that Hercules uses to chop off its heads, though this may take a very long time. Just like for <a href="https://ioc.exchange/tags/Goodstein" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Goodstein</span></a> sequences, Kirby and Paris showed that it cannot be proven in <a href="https://ioc.exchange/tags/Peano" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Peano</span></a> arithmetic alone</p>
xameer<p>Hydra will eventually be killed, regardless of the strategy that Hercules uses to chop off its heads, though this may take a very long time. Just like for <a href="https://ioc.exchange/tags/Goodstein" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Goodstein</span></a> sequences, Kirby and Paris showed that it cannot be proven in <a href="https://ioc.exchange/tags/Peano" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Peano</span></a> arithmetic alone</p>
xameer<p>Since <a href="https://ioc.exchange/tags/Peano" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Peano</span></a> arithmetic cannot prove its own consistency by <a href="https://ioc.exchange/tags/G%C3%B6del" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Gödel</span></a>'s second incompleteness theorem, this shows that Peano arithmetic cannot prove the strengthened finite Ramsey theorem.</p>
xameer<p>Since <a href="https://ioc.exchange/tags/Peano" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Peano</span></a> arithmetic cannot prove its own consistency by <a href="https://ioc.exchange/tags/G%C3%B6del" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Gödel</span></a>'s second incompleteness theorem, this shows that Peano arithmetic cannot prove the strengthened finite Ramsey theorem.</p>
xameer<p>there is an integer n such that if there is a sequence of rooted trees T1, T2, ..., Tn st Tk has at most k+10 vertices, then some tree can be <a href="https://ioc.exchange/tags/homeomorphically" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>homeomorphically</span></a> embedded in a later one"<br>is provable in <a href="https://ioc.exchange/tags/Peano" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Peano</span></a> arithmetic, but shortest proof &gt; A(1000), where A(0)=1 and A(n+1)=2A(n)</p>
xameer<p>there is an integer n such that if there is a sequence of rooted trees T1, T2, ..., Tn st Tk has at most k+10 vertices, then some tree can be <a href="https://ioc.exchange/tags/homeomorphically" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>homeomorphically</span></a> embedded in a later one"<br>is provable in <a href="https://ioc.exchange/tags/Peano" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Peano</span></a> arithmetic, but shortest proof &gt; A(1000), where A(0)=1 and A(n+1)=2A(n)</p>
xameer<p>Gödel: any <a href="https://ioc.exchange/tags/recursive" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>recursive</span></a> system that is sufficiently powerful, such as <a href="https://ioc.exchange/tags/Peano" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Peano</span></a> arithmetic, cannot be both consistent and syntactically complete.</p>
xameer<p>Gödel: any <a href="https://ioc.exchange/tags/recursive" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>recursive</span></a> system that is sufficiently powerful, such as <a href="https://ioc.exchange/tags/Peano" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Peano</span></a> arithmetic, cannot be both consistent and syntactically complete.</p>