Jason (jcreed) wrote,

In the shower this morning an idea ocurred to me which, I think, forms the core of a proof that coverability for VCSs is decidable. First steps towards decidability of VCS reachability, which would be an interesting partial result, I think. There are still many things in [Kosaraju 82] that do not lend themselves to obvious generalization, but I'm glad there still seems to be a way of using Kruskal's-Theorem-like tools to show the finiteness of coverability trees in the more general case.

Got Tartan stuff partially done pretty quickly. But the last 10% took the other 90% of the time. As always, if I leave anything undone, it takes much longer than I expect to get it done in the evening when all of the office computers are in high demand. But I scanned in some other stuff to fill the trusted mech-shaped hole and all is more or less well. I am still very eager to see how comic-3-or-maybe-not-3 turns out. I long to have type coffeemaker!

Also: I thought the weather was pretty nice yesterday. It was just unspeakably, beautifully right out today. I don't remember ever quite experiencing a day like this. If I had perfect autumn days of my childhood to look back on and wish for, they would be like this one. The winds were particularly blustery (but not cold) and so the existing standard fall ground cover got a considerable bit thicker, and made everything smell like crispy dry leaves and moist soil from the early-morning rain. And the temperature wandered casually from that perfect undifferentiated room-temperature feeling to warm, to slightly and pleasantly cool in the evening. Some nights the huge, now golden-leaved tree on the corner of Forbes and Beeler catches the sunset just right and seems to almost glow against the deepening blue of the sky rather than merely reflect the light and I feel weirdly unreal, or maybe I should say that I feel too real, a living person standing inside a painting.

I suppose I could have spent more time outside than I did. I don't really seem to every consciously prioritize just sitting outside, even on days like this. But I did walk to and from Oakland twice, and it was nice. The first time was for lunch at Primanti, and during the second I got some headphones, finally, to replace the broken pair that I had.

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