• affiliate@lemmy.world
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    2 months ago

    that would be a lot clearer. i’ve just been burned in the past by notation in analysis.

    my two most painful memories are:

    • in the (baby) rudin textbook, he uses f(x+) to denote the limit of _f _from the right, and f(x-) to denote the limit of f from the left.
    • in friedman analysis textbook, he writes the direct sum of vector spaces as M + N instead of using the standard notation M ⊕ N. to make matters worse, he uses M ⊕ N to mean M is orthogonal to N.

    there’s the usual “null spaces” instead of “kernel” nonsense. ive also seen lots of analysis books use the → symbol to define functions when they really should have been using the ↦ symbol.

    at this point, i wouldn’t put anything past them.