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Comment by whistl034 | Hacker News Reader

Is there a font missing or something? When I try to read the paper, every instruction dependency is displayed as x ? y, with a question mark between each object, even when the author implies there is some difference between x ? y and x ? y. I'm sure there is supposed to be some other characters there, because without them the paper makes no sense.

Perhaps it's something that only shows up properly on Windows computers?

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I thought it's going to be mojibake, but it's not of the � variety, just a regular question mark. One candidate is the "precedes" symbol: https://codepoints.net/U+227A

The precedes symbol is < and the parallel symbol is |.

https://www.cprogramming.com/parallelism.html - another copy without this problem.

You skimmed too fast, from that same article:

> We say that an instruction x precedes an instruction y, sometimes denoted x ? y, if x must complete before y can begin. In a diagram for the dag, x ? y means that there is a positive-length path from x to y. If neither x ? y nor y ? x, we say the instructions are in parallel, denoted x ? y. The figure below illustrates a multithreaded dag:

That quote presents exactly the confusion for GP. x ? y is described to mean both that x precedes y and that x and y are in parallel. It suggests that something got lost in translation here.

https://www.cprogramming.com/parallelism.html

Non-archive link: x < y (x precedes y) and x | y (x is parallel with y).

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