Stories
Slash Boxes
Comments

SoylentNews is people

posted by Fnord666 on Monday November 05 2018, @02:29PM   Printer-friendly
from the it-means-it's-composite dept.

Submitted via IRC for Bytram

What Is an "Almost Prime" Number?

When I saw a math paper with the phrase "almost prime" in the title, I thought it sounded pretty funny. It reminded me of the joke about how you can't be a little bit pregnant. On further thought, though, it seems like someone whose pregnancy is 6 weeks along and who hasn't yet noticed a missed period is meaningfully less pregnant that someone rounding the bend at 39 weeks who can balance a dinner plate on their belly. Perhaps "almost prime" could make sense too.

A number is prime if its only factors are 1 and itself. By convention, the number 1 is not considered to be prime, so the primes start 2, 3, 5, 7, 11, and so on. Hence, a prime number has one prime factor. A number with two prime factors, like 4 (where the two factors are both 2) or 6 (2×3) is definitely less prime than a prime number, but it kind of seems more prime than 8 or 30, both of which have three prime factors (2×2×2 and 2×3×5, respectively). The notion of almost primes is a way of quantifying how close a number is to being prime.


Original Submission

 
This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
  • (Score: 1, Informative) by Anonymous Coward on Monday November 05 2018, @05:06PM (2 children)

    by Anonymous Coward on Monday November 05 2018, @05:06PM (#758061)

    Playing the lottery almost always leads to a loss.

    Playing the lottery not always leads to a loss.

    Sure, both statements are true. But the first one contains more useful information.

    Starting Score:    0  points
    Moderation   +1  
       Informative=1, Total=1
    Extra 'Informative' Modifier   0  

    Total Score:   1  
  • (Score: 2) by requerdanos on Monday November 05 2018, @05:22PM

    by requerdanos (5997) Subscriber Badge on Monday November 05 2018, @05:22PM (#758067) Journal

    You probably weren't in doubt, as the author of at least the headline of this story seems to be.

  • (Score: 2) by kazzie on Monday November 05 2018, @06:26PM

    by kazzie (5309) Subscriber Badge on Monday November 05 2018, @06:26PM (#758110)

    The second statement is better for marketing purposes, though.