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Dec 22 |
comment |
Anti-compactness
Does the term "anti-compact" in this sense have a history or did you just invent it? It has been used for spaces in which every compact set is finite; see Paul Bankston, The total negation of a topological property, Illinois J. Math. 23 (1979), 241-252. |
Dec 22 |
comment |
For any two noncrossing partitions $p, q$ of $n$, is the graph of geodesics from $p$ to $q$ in $NC(n)$ connected?
What is a noncrossing partition of a number $n$? You don't mean partitions of the set $[n]=\{1,2,\dots,n\}$? |
Dec 21 |
revised |
Are the following interpretations elementarily equivalent?
English grammar |
Dec 21 |
comment |
Are the following interpretations elementarily equivalent?
They are elementarily equivalent. Use the Ehrenfeucht-Fraisse game to prove this. By the way this question belongs on Mathematics Stack Exchange. |
Dec 21 |
suggested | approved edit on Are the following interpretations elementarily equivalent? |
Dec 18 |
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Rooks in three dimensions
I am confused. In the first sentence, you say it's still open whether or not any finite number of rooks can force checkmate. In the second sentence, you say that 96 rooks can force checkmate. I suspect that it's the first sentence which I am parsing incorrectly, but in that case I have no idea what it is supposed to mean. |
Dec 17 |
comment |
finding dominating cycles in $2K_2$-free graphs
Where, by the "complement" of a cycle $C$ in a graph $G$, you really mean the graph $G-V(C)$. Did I guess right? |
Dec 13 |
revised |
Strongest large cardinal axiom compatible with $V = L$?
Corrected a word in the quotation. |
Dec 13 |
suggested | approved edit on Strongest large cardinal axiom compatible with $V = L$? |
Dec 8 |
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Magic trick based on deep mathematics
Isn't it risky to do magic tricks that require a member of the audience to carry out a computation? What do you do if Alice botches the computation? |
Dec 5 |
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Famous mathematical quotes
The way I heard it: "If I have not seen as far as others, it is because I have stood in the footprints of giants." |
Nov 29 |
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Finite graphs that realize all types over $n$-element sets
Your example has only $15$ vertices, not $30$. |
Nov 28 |
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Inclusion-preserving bijection between subsets of cardinality k and n-k
You only thought about showing that the bipartite graph satisfies Hall's condition? You didn't try to do it? |
Nov 28 |
answered | Inclusion-preserving bijection between subsets of cardinality k and n-k |
Nov 26 |
comment |
Does Nelson try to prove PA inconsistent directly?
If PA proves the statement "PA is consistent", that would for sure establish the inconsistency of PA. If PA proves "PA is inconsistent", that only proves the inconsistence of PA + Con(PA) or stronger theories such as ZF. |
Nov 25 |
awarded | Yearling |
Nov 24 |
comment |
Is it possible to define higher cardinal arithmetics
"Hyperoperations" on ordinal numbers have been treated e.g. by Doner & Tarski, but of course you are aware of that. |
Nov 22 |
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Coloring algorithm maximising color difference between neighbors
This is a specialization of the graph T-coloring problem, which is said to have application to [frequency assignment](www.inets.rwth-aachen.de/pub/Frequency_allocation_for_WLAN.pdf) problems. |
Nov 20 |
comment |
Minimal hypergraphs with respect to separation
@AlexDegtyarev, I see. I don't think that by "minimal" the OP means a $T_1$ structure $E$ which is a subset of every $T_1$ structure; I think he means a $T_1$ structure $E$ such that no proper subset of $E$ is a $T_1$ structure. This is the usual meaning of "minimal element" in English; the other would be called "minimum" or "least element". |
Nov 20 |
revised |
Minimal hypergraphs with respect to separation
added 7 characters in body |