I use xe/xem or they/them pronouns ATM.

I wanna be a cat girl! Or a cat enby perhaps. Nyan.

  • 4 Posts
  • 32 Comments
Joined 2 years ago
cake
Cake day: June 11th, 2023

help-circle
  • Checks I Should Have Done Before Posting

    Sorry for the self-posting. I just wanted to share my post-hoc file checks since it was due-diligence I didn’t think of until after I shared.

    TLDR: I redirected into a file and inspected it at least enough to say I received an mkv container with an h264 video and opus audio.

    Caveats

    1. I am not in any way knowledgeable about security.
    2. You can do weird things with some files. I have no idea if mkv, opus, or h264 have comments or chimeras. See talks by Corkami for more information.
    3. Quad9 uses a dynamic TXT record to let the user know if they have configured their DNS resolver correctly, so I imagine you could receive a different file than I did. I have included a SHA-512 checksum for convenience which only tells you anything if you trust me for some reason.

    Details

    I ran the command from my post in a world-readable directory with >mystery_video_file substituted for | mpv -- - and inspected the download with

    sudo --user=nobody -- file -- mystery_video_file

    which output

    mystery_video_file: Matroska data

    I ran rename --last -- '' '.mkv' mystery_video_file # the '' is the empty string delimited with apostrophes and then

    sudo --user=nobody -- ffprobe -hide_banner -- mystery_video_file.mkv

    which output

    Input #0, matroska,webm, from ‘mystery_video_file.mkv’: Metadata: COMPATIBLE_BRANDS: isommp42 MAJOR_BRAND : mp42 MINOR_VERSION : 0 ENCODER : Lavf60.16.100 Duration: N/A, start: -0.007000, bitrate: N/A Stream #0:0: Video: h264 (High), yuv420p(tv, bt709, progressive), 256x144 [SAR 1:1 DAR 16:9], 25 fps, 25 tbr, 1k tbn (default) Metadata: HANDLER_NAME : ISO Media file produced by Google Inc. Created on: 05/29/2024. VENDOR_ID : [0][0][0][0] ENCODER : Lavc60.31.102 libx264 Stream #0:1(eng): Audio: opus, 48000 Hz, stereo, fltp (default) Metadata: HANDLER_NAME : ISO Media file produced by Google Inc. Created on: 05/29/2024. VENDOR_ID : [0][0][0][0] ENCODER : Lavc60.31.102 libopus

    If you trust me and not the presenter for some inexplicable reason, the SHA-512 checksum for the video is “24345bd3ca8015c14a7d5d63d6b2a40f9d0f8c0307a65996226a496f121fa5ae934718cf58090f43ee67bc250b06804f23c73688cc871c15c1ba18d79b1a82a8”.






  • I’d imagine you want something defined recursively like multiplication

    • ( 0x = 0 )
    • ( xy = x(y-1)+ x ) ( y > 0 ).

    So it needs to be

    • ( x^0 = c ) (c is some constant)
    • ( x^y = xx^{y-1} ) (( y > 0 ) (to see why, replace multiplication with exponentiation and addition with multiplication). So what could ( c ) be? Well, the recursive exponentiation definition we want refers to ( x^0 ) in ( x^1 ). ( x^1 ) must be ( x ) by the thing we wish to capture in the formalism (multiplication repeated a single time). So the proposed formalism has ( x = x^1 = xx^0 = xc ). So ( cx = x ) hence ( c = 1 ), the multiplicative identity. Anything else would leave exponentiation to a zeroth power undefined, require a special case for a zeroth power and make the base definition that of ( x^1 ), or violate the intuition that exponentiation is repeated multiplication.

    On an unrelated note, it’d be nice if Lemmy had Mathjax. I just wrote all this on mobile with that assumption, and I’m not rewriting now that I know better.