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yozh.org | ||
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cronokirby.com
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| | | | | - Read more: https://cronokirby.com/posts/2021/02/tychonoff-theorem-and-zorns-lemma/ | |
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djalil.chafai.net
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| | | | | This post is mainly devoted to a probabilistic proof of a famous theorem due to Schoenberg on radial positive definite functions. Let us begin with a general notion: we say that \( {K:\mathbb{R}^d\times\mathbb{R}^d\rightarrow\mathbb{R}} \) is a positive definite kernel when \[ \forall n\geq1, \forall x_1,\ldots,x_n\in\mathbb{R}^d, \forall c\in\mathbb{C}^n, \quad\sum_{i=1}^n\sum_{j=1}^nc_iK(x_i,x_j)\bar{c}_j\geq0. \] When \( {K} \) is symmetric, i.e. \( {K(x,y)=K(y,x)} \) for... | |
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thehousecarpenter.wordpress.com
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| | | | | As usual, this post can be viewed as a PDF. Theorem (Boundedness Theorem). A continuous real-valued function on a closed interval is bounded. Proof. Suppose f is such a function and [a,?b] is its domain. First, observe that for every c?[a,?b], since f is continuous at c, there is a positive $latex \delta \in {\mathbb... | |
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mycqstate.wordpress.com
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| | | This post is a follow-up on some somewhat off-hand comments that I made earlier regarding the notion of truth in a "proof-based" discipline such as pure mathematics or theoretical computer science. Since the former is easier to circumscribe and also has a larger literature available on it, for the purposes of the post I will... | ||
