Carl Mummert

Marshall University

science.marshall.edu/mummertc

Age: 36

I work in mathematical logic. My main areas of interest are arithmetic, reverse mathematics, computability, and proof theory.
5h
comment Why does a complete binary tree of $n$ leaves have $2n-1$ nodes?
@awellwisher: yes, I believe so. Also, spaces in mentions work fine, as long as the first name is at least 3 letters long.
6h
comment An easy example of a non-constructive proof without an obvious "fix"?
@Stephen Montgomery-Smith: the normal terminology used to talk about constructive mathematics does not worry about computational complexity. So for example every natural number is "constructive" even if it cannot be written in the physical universe. But your point is valid in that they indeed don't worry about efficiency. (At the same time, $\pi$ is also a constructive real, and I have no idea what the 100th digit of $\pi$ is or how to easily compute it.)
14h
awarded Good Answer
1d
awarded Enlightened
1d
awarded Nice Answer
1d
comment Given a positive integer n show that there exists one and only one pair of integers h and k with 0 ≤ h < k such that n = 1/2 k(k − 1) + h.
This question is not about mathematical logic, so I retagged it.
1d
revised Given a positive integer n show that there exists one and only one pair of integers h and k with 0 ≤ h < k such that n = 1/2 k(k − 1) + h.
edited tags
1d
comment Assigning tables for Speed Networking session
@Jyrki Lahtonen: the major remaining problem is that the question is still a PSQ, and the OP has not improved it (or even been active since Jan 20). Unlike delete/undelete wars, close/reopen wars don't need moderator attention, because each person only can vote one time.
1d
awarded Mortarboard
1d
comment First-order logic representation
For the second one, the way to express "only" is with an implication.
1d
comment First-order logic representation
That will work if the domain is the set of differences between cats and tigers.
1d
comment I want to help but I cannot because the questions are already answered by high-level users
I am suspicious about any link between true quality and rep. I think that rep is more a measure of time spent on the site and question selection.
1d
comment What makes an answer community wiki, and when can this be undone?
@Arthur Fischer: and when I don't want to earn rep for a particular answer?
1d
answered Someone edited my answer... years after I deleted it!
1d
comment What makes an answer community wiki, and when can this be undone?
@Arthur Fischer: I see the point of the SE blog that it would be nice to have a different way of saying "don't earn rep for this post". But, until we have a different way of doing that, we will still need to use CW for that purpose. Unless I have missed some alternative method that already exists?
1d
comment What makes an answer community wiki, and when can this be undone?
@Git Gud: on MSE, like MathOverflow, CW is indeed for questions that don't have objective answers, and it is a reputation denial mechanism. This is another example, I think, of the SE blog being out of sync with the reality of particular communities. When I mark my own questions or answers as CW, it is to avoid reputation for them, not to encourage others to edit them.
1d
comment Someone edited my answer... years after I deleted it!
I always thought that the fact that I can see my deleted answers means that someone else must also be able to. But, for something that will really blow you mind, I think it is the case that moderators can also see my deleted comments even though I can't.
1d
answered I want to help but I cannot because the questions are already answered by high-level users
2d
awarded Nice Answer
2d
awarded constructive-mathematics
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