On Mon, Oct 12, 2020, 1:43 AM Greg Ewing greg.ewing@canterbury.ac.nz wrote:

On 12/10/20 3:44 pm, Wes Turner wrote:

[Microscopic] black holes do deal with infinity in certain regards.)

Not really. General relativity predicts that matter will collapse into a point of zero size and infinite density inside a black hole. But that's more likely to mean that GR is wrong under such extreme conditions, than to mean that there's actually a singularity at the centre of a black hole.

Whether scalar times infinity is relevant to describing the progression of a black hole / wormhole / whitehole is something that cannot be assessed without symbolic mathematics; which IEEE-754 (and the proposed Python implementation of IEEE-754's alternative to ZeroDivisionError) cannot solve for.

In any case, this doesn't have anything to do with the present discussion. You can't use physics to prove things about maths, or vice versa.

OT: There are certainly applications for (scalar times) float and non-float infinity. ZeroDivisionError may be more desirable than attempting to build a CAS in stdlib; or even handling non-float math.inf in stdlib.

Notably, the https://en.wikipedia.org/wiki/Bekenstein_bound is limited to certainly less than infinity, but there is disagreement in other forums over whether black holes have an event horizon or an apparent horizon.

"the absence of event horizons mean that there are no black holes – in

the sense of regimes from which light can't escape to infinity."

https://en.wikipedia.org/wiki/Event_horizon

"It's just inf; the other terms are then irrelevant" is insufficient for many applications.

Where are the standard library and third-party tests that catch ZeroDivisionError?

Something this be an appropriate migration strategy for implementing IEEE-754 inf/+inf/-inf:

from __future__ import floatinfinity