The Math Forum



Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.


Math Forum » Discussions » sci.math.* » sci.math

Topic: Re: Infinity - Infinity = Infinity?
Replies: 3   Last Post: Oct 5, 2017 9:24 AM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Markus Klyver

Posts: 702
Registered: 5/26/17
Re: Infinity - Infinity = Infinity?
Posted: Oct 5, 2017 9:24 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

Den onsdag 4 oktober 2017 kl. 22:30:07 UTC+2 skrev Doctor Allan:
> You may wonder: CAN an infinite value be taken from an infinite quantity and still leave an infinity quantity? The answer is yes. For instance, the cardinality of the set of natural numbers is infinite. Remove from this set the infinite elements which are even, and you are left with the infinite set of odd positive numbers.
>
> You may wonder: MUST an infinite value, when taken from an infinite value, always yield an infinite value? The answer is no. For example, take the set of natural numbers, a set with infinite cardinality. Remove from this the set of natural numbers, a set with infinite cardinality. The remainder is an empty set, with 0 elements.
>
> Conclusion:
> When substracting infinity from infinity, you can, depending on how you define subtraction and your infinities, wind up with infinity or a finite value.


Much in the same way, you can't really add infinite quantities either without being very careful. In the complex plane, two arbitrary large quantities can be zero when added.



Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© The Math Forum at NCTM 1994-2017. All Rights Reserved.