TechBrief — تازه‌ترین اخبار فناوری

The Best Movies to Stream This Month (April 2026)

28 Years Later: The Bone Temple, Crime 101, and Deathstalker are among the films deserving of your eyeballs this month

The ‘Lonely Runner’ Problem Only Appears Simple

Take a group of runners circling a track at unique, constant paces. Answering the question of how many will always end up running alone, no matter their speed, has vexed mathematicians for decades.

America Lost the Mandate of Heaven

Article URL: https://geohot.github.io//blog/jekyll/update/2026/04/18/america-mandate-of-heaven.html

Comments URL: https://news.ycombinator.com/item?id=47814073

Points: 6

# Comments: 2

Category Theory Illustrated – Orders

Article URL: https://abuseofnotation.github.io/category-theory-illustrated/04_order/

Comments URL: https://news.ycombinator.com/item?id=47813668

Points: 61

# Comments: 13

Amiga Graphics

Article URL: https://amiga.lychesis.net/

Comments URL: https://news.ycombinator.com/item?id=47813566

Points: 58

# Comments: 2

It is incorrect to "normalize" // in HTTP URL paths

Article URL: https://runxiyu.org/comp/doubleslash/

Comments URL: https://news.ycombinator.com/item?id=47813454

Points: 29

# Comments: 18

Once close enough for an acquisition, Stripe and Airwallex are now going after each other

For most of its life, Airwallex and Stripe have mostly operated in different geographies, selling to different buyers. That's changing.

Show HN: Sfsym – Export Apple SF Symbols as Vector SVG/PDF/PNG

I found myself reaching for SF Symbols' 'Copy Image As…' quite often during agentic design sessions, so I made a command-line tool that the agent can use by itself. It exports Apple SF Symbols as SVG, PDF, or PNG.

The vector paths come directly from macOS's symbol renderer. Internally it reaches a private ivar on NSSymbolImageRep to get the CUINamedVectorGlyph, draws into a CGPDFContext, then walks the PDF content stream back out as SVG `d` commands. The output matches what the system draws, rather than an approximation traced from rasters.

A few things about it:

- Every subcommand accepts `--json`, and `sfsym schema` returns a machine-readable description of the whole CLI. - Symbol enumeration reads the OS's Assets.car BOM tree, so the list of 8,300+ names stays current with macOS updates without a version table in the binary. - Each SVG `` carries a `data-layer` attribute, so you can retheme in CSS without touching geometry.

It's been saving me a bunch of clicking. Please let me know if you have any other ideas for it.

Comments URL: https://news.ycombinator.com/item?id=47812964

Points: 3

# Comments: 0

Show HN: I made a calculator that works over disjoint sets of intervals

I've been studying interval arithmetic for the past few weeks and it's a really interesting field because while there is a ton of super interesting research published over the past decades, it has never really gotten the recognition that it deserves, IMO.

One reason for this is that standard interval arithmetic has really poor handling of division by intervals containing zero. If you compute 1 / [-1, 2] in regular interval arithmetic, you get either [-∞, +∞], or you have to say that the operation is undefined. Both solutions are virtually useless. The real answer of course is [-∞, -1] U [0.5, +∞]: i.e. a union of two disjoint intervals.

This is useful because you can confidently exclude a non empty set of the real numbers ([-1, 0.5]) from the set of possible values that you can get by dividing 1 by a number between -1 and 2.

But this definition of interval division yields a value that is not an interval. This is a problem if you want to define a closed arithmetic system, where you can build and evaluate arbitrary expression over interval values.

(This behavior extends to any non continuous function like tan() for example, which is implemented in my project - not without difficulties!)

Well the obvious solution is to define your arithmetic over disjoint unions of intervals. This is the subject of a 2017 paper called "Interval Unions" by by Schichl, H., Domes, F., Montanher, T. and Kofler, K..

This open-source project I made implements interval union arithmetic in TypeScript in the form of a simple interactive calculator, so you can try it out for yourself! The underlying TypeScript library is dependency free and implements interval union arithmetic over IEEE 754 double precision floats (JS native number type) with outward rounding. This guarantees accuracy of interval results in the presence of rounding issue inherent to floating point.

Comments URL: https://news.ycombinator.com/item?id=47812341

Points: 152

# Comments: 27

Casus Belli Engineering

Article URL: https://marcosmagueta.com/blog/casus-belli-engineering/

Comments URL: https://news.ycombinator.com/item?id=47812331

Points: 38

# Comments: 12