2026-04-06T20:10:12Z https://yabu.me baptiste https://yabu.me/npub1sdzd97zht6e4nvmxvhkywt2elensrqvugvq79jj9ef43zx8j2rmsgwm07l https://cdn.masto.host/vissocial/accounts/avatars/109/248/128/824/284/467/original/b6a6781be253255f.jpg https://cdn.masto.host/vissocial/accounts/avatars/109/248/128/824/284/467/original/b6a6781be253255f.jpg https://yabu.me/nevent1qqspa5e5xul6ze4etk6na5ktyl6hc6k4zxlv64h2r6g39m9yepwstdszyzp5f5hc2a0txkdnvej7c3edt8lxwqvpn3psrck2gh9xkygc7fg0wzy6h6w &#34;Yes, I agree with everything you said – it&#39;s antithetical to learning, it&#39;s led by terrible companies, etc. — but I think we should encourage students to use it because it can&#39;t be avoided and they&#39;ll be left behind and we&#39;ll look ridiculous if we don&#39;t jump on this train.&#34;<br/><br/>How&#39;s your Monday going 2025-09-21T23:36:32Z https://yabu.me/nevent1qqst4jm0cg7dp2xr2rd5tqnunmwr95ajzk80qayr0pykwk5y8pmy6nczyzp5f5hc2a0txkdnvej7c3edt8lxwqvpn3psrck2gh9xkygc7fg0w7m0w3j In reply to <a href='/nevent1qqs06psrcq5hmf9p6fat8wq478vv09sp4vuyqrppuwna6w4v007qf8sd8209p'>nevent1q…209p</a><br/>_________________________<br/><br/>I often wonder if things might get clearer/easier when using index notations from differential geometry, rather than the vector-looking-but-not-a-vector nabla. For example, that (v ⋅∇) operator is a bit tricky to manipulate (not sure how it&#39;s to be done in non-cartesian systems of coordinates) 2025-05-19T17:01:51Z https://yabu.me/nevent1qqs068kkykcx9q6wzxrgh3hlhyrpztfg68z4tuwszl58avzm369xmmqzyzp5f5hc2a0txkdnvej7c3edt8lxwqvpn3psrck2gh9xkygc7fg0wfmx3pm In reply to <a href='/nevent1qqsqv9m3ea6yn45avsc7z9gstu2uamjexl6dqatpqc3zny3vadd7lcc9ld8z3'>nevent1q…d8z3</a><br/>_________________________<br/><br/>funny, I just had tabs open in my browser regarding conservation of helicity in electromagnetic fields – things like Lipkin&#39;s &#39;zilch&#39;, dual-symmetric media, Kerker condition, etc.<br/><br/><a href="https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.104.163901">https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.104.163901</a><br/><br/><a href="https://www.mdpi.com/2073-8994/11/9/1113">https://www.mdpi.com/2073-8994/11/9/1113</a> 2025-05-19T14:22:00Z https://yabu.me/nevent1qqsdqhqx6mq44c5ppj4zu855z57mk3m4f0az5p7jxjvry8zuzgs9a4czyzp5f5hc2a0txkdnvej7c3edt8lxwqvpn3psrck2gh9xkygc7fg0wrz9kzq In reply to <a href='/nevent1qqswypnhg5xquztmv2u8ac3a67yrcev0mmy4lfaefq3vfqucdgpylts3wsz7d'>nevent1q…sz7d</a><br/>_________________________<br/><br/>Incidentally, do you think this might provide an intuitive interpretation/example of the less-intuitive terms appearing in the Maxwell stress tensor? A colleague of mine once alluded to this magnetic field lines-as-rubber-bands intuition, but didn&#39;t elaborate further. <br/>I (think I) understand the ∇(E²) intuitively (e.g optical tweezers where a trapped dipole wants to minimise its energy), and the Poynting one (light sail), but the (E•∇)E (or ∇x∇x whence it appeared) eludes me.<br/> <img src="https://cdn.masto.host/vissocial/media_attachments/files/113/722/465/568/385/103/original/b8f20f250fd0c83a.png"> <br/> 2024-12-27T02:40:48Z https://yabu.me/nevent1qqsgcch0ala05g2j8ka7t7fu5vvmzl3afeedj3dadnsak3j9gtdndggzyzp5f5hc2a0txkdnvej7c3edt8lxwqvpn3psrck2gh9xkygc7fg0wjpn5wf Me, opening google maps: <br/>&#34;I wonder if there&#39;s interesting teaware produced around where I&#39;ll be staying—Suzhou&#34;<br/><br/>&#34;Oh&#34; 2024-11-16T21:48:32Z https://yabu.me/nevent1qqs2ddx5xryumlj8ejc2ynjg8z3aeew6zequeusm8gpq0sjgac8rvlgzyzp5f5hc2a0txkdnvej7c3edt8lxwqvpn3psrck2gh9xkygc7fg0wnfs3fv In reply to <a href='/nevent1qqs22nmsy47adgrc298ntvx9tsmjq2x3v64zsrtapy4zypfntuh9ync5wpw5g'>nevent1q…pw5g</a><br/>_________________________<br/><br/>I will be very disappointed if I don&#39;t read further down in the comments, that there is in fact an entire subfield of mathematics defining concepts such as these, and extending them far beyond the point of comprehensibleness—and of course a dedicated set of macros on CTAN 2024-11-16T03:02:08Z https://yabu.me/nevent1qqs8x383uv0aeetdpne480lgzxm7uy3602amgkte7j65wr4qrfru08gzyzp5f5hc2a0txkdnvej7c3edt8lxwqvpn3psrck2gh9xkygc7fg0wkhj4ga I&#39;m looking for black ink that is i) very black, ii) water soluble, iii) dye, not pigment based<br/>Any recommendations?<br/><br/>#FountainPens<br/>#FountainPen<br/>#FountainPenInk 2024-10-27T20:52:25Z