My past research interests included differential algebraic equations, nonlinear analysis and relations between symmetries and structural properties.

I recently investigated hierarchical structures, starting from group cohomology, continuing with semi-group theory and ending with lattices and universal algebra.

25m
reviewed Leave Open Scheduling Problem Optimisation using LP solvers
33m
reviewed Leave Open Question on NP $\cap$ coNP
35m
reviewed Close K-nearest neighbor: double instances in training and test set
12h
reviewed Approve suggested edit on User input is entered vertically and not horizontally in C++ Need help
12h
reviewed Approve suggested edit on Stateless pseudorandom/hash algorithm for ℤⁿ → [0,1)
1d
revised Relativized world where $L^A=NP^A$
added 30 characters in body
1d
accepted Relativized world where $L^A=NP^A$
1d
comment Relativized world where $L^A=NP^A$
It's a bit embarrassing to ask a question with such a trivial well known answer. However, compared to actually spending time trying to separate $L$ from $P$ by simple approaches like looking at the $P$-complete Horn-SAT problem, it makes sense to first ask whether there are known mathematical reasons why we expect that separating $L$ from $NP$ will be difficult.
1d
answered Relativized world where $L^A=NP^A$
1d
answered Why do the interesting antihomomorphisms tend to be involutions?
2d
reviewed Leave Closed Does every infinite recursive language contain an infinite regular subset?
2d
comment sets of axioms for LADR automated theorem provers
I think the TPTP library also contains a utility called TPTP2X, which can convert to the input format of many different ATP systems. As you can see from the linked page, prover9 is also among the supported TPTP2X Output Formats.
2d
awarded Yearling
2d
awarded Yearling
May
20
comment Can well-formed formulas in predicate logic for a given signature be recognized in LOGSPACE?
For the second element, we actually also have to add a marker that the stack will contain exactly one element after it is popped, i.e. that it is possible to accept then.
May
20
answered Can well-formed formulas in predicate logic for a given signature be recognized in LOGSPACE?
May
19
comment sets of axioms for LADR automated theorem provers
Don't forget to also use mace4, I found it even more useful than prover9. LADR just means "Library for Automated Deduction Research", and has little to do with the file format. The-E-theorem-prover can directly use TPTP programs. But I found it quite easy to convert between the different input formats, so I wouldn't worry too much about the file format. Here I describe some of my own experiments with prover9 & co.
May
19
comment Spatial data structures are part of Computational Geometry?
@Mr.Grey The field is called computational geometry, and analyzes both data structures and algorithms. The meaning of "data structure" is quite well defined, no need to muddle with its meaning by calling it algorithm. The meaning of "algorithm" is more difficult, because good algorithm design is modular, but what it the actual algorithm, if all of its parts can be exchanged. (You want to have the parts exchangable, so that you can better test and debug your implementation, especially when things go wrong...)
May
19
comment Spatial data structures are part of Computational Geometry?
@Mr.Grey Why do you think that a "data structure" is called an "algorithm"? I'd rather say that some geometric algorithms will use such data structures, so you have to talk about the data structure, in order to be able to talk about the algorithm. That's part of what I meant when I said that these data structures are part of computational geometry!
May
19
answered Spatial data structures are part of Computational Geometry?
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