Parallel Transport
Hot off the press — more spatial infinity stuff; symmetries and charges; with Ibrahim Shehzad :
New paper on angular momentum of Einstein-Maxwell at null infinity with Beatrice Bonga and Alexander M. Grant. Go get it!
So Chrome and Safari don’t like my site’s CSS grids unless I put a “width: 100%” on the Grid containers. No idea why but thanks to for the fix!
anything violating the uniqueness theorems would be fair game: asymptotics, higher dimensions, modified gravity… But getting an explicit counter-example seems pretty hard. Would be nice to have some local existence proof though not sure how to even approach that!
btw: for Einstein-Maxwell the electric potential being constant is a result by Carter in some old-ish Les Houches publication that I can’t find right now. I also expect static to imply that the electric flux/area element is constant, but I really have no idea how to show that without using global results like Birkhoff’s theorem or uniqueness (in the stationary case). Somehow our guts know about global results that our brains don’t!

SVG in Javascript

To use fragmentioner and marginalia on my site, I want to insert SVG icons into the HTML pages. Sounds simple unless you check all the browsers — Chrome and Opera just behave weirdly!

Full post: SVG in Javascript

in SVG

While creating an animated SVG logo for we ran into a strange problem where the SVG would display in some browsers and not in others. The issue is the different ways browsers handle XML — yes SVG is XML! So here is the problem and its solution.

Full post: in SVG

Placeholder Images

The size of my images changes fluidly with my responsive layout. Since the browser does not know their heights a priori, the space collapses while the images are still loading. Once the images load the entire page reflows and the rest of the content jumps around to make space for them. It would be much better if the space for the images was reserved from the start and, as a bonus, if some lower resolution version of the images displayed, while the images load. Here is how I do it.

Full post: Placeholder Images

Equal Height Images with Flexbox

Images on the Web have a mind of their own. Want to place two fluid images side by side so that their heights are always equal? Flexbox to the rescue!

Full post: Equal Height Images with Flexbox

The Web’s Arrow of Time

I was looking into adding some navigation links to my post feed/archive pages, when I ran into an old confusion of mine. The Web has a completely messed up arrow of time!

Full post: The Web’s Arrow of Time