11,559 reputation
2861
bio website andrej.com
location Slovenia
age 43
visits member for 4 years, 1 month
seen 19 hours ago

I am a professional mathematician and theoretical computer scientist (what is the difference?) . My area of work is a mix of logic, semantics, programming languages, category theory, constructive mathematics and computability.


7h
awarded  Explainer
1d
comment Purely functional uniquely-represented deques
Doubly-linked lists are only uniquely represented if one cannot compare pointers.
Sep
24
revised Dependent Sums and Products
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Sep
24
answered Dependent Sums and Products
Sep
23
comment Are computable functions always monotone?
It is not clear what monotonicity you are referring to. If you are referring to domain-theoretic semantics, then yes, every computable map is monotone. But if you are just asking whether every computable map $\mathbb{N} \to \mathbb{N}$ is monotone for the usual order on $\mathbb{N}$, then the answer is no, obviously. You should clarify your question.
Sep
17
answered Explaining monad transformers in categorical terms
Sep
16
comment Do Genetic Algorithms Expect a Independent Search Space
You definitely do not mean "separable", see en.wikipedia.org/wiki/Separable_space
Sep
10
revised Computability of infinite-dimensional vector space
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Sep
9
revised Computability of infinite-dimensional vector space
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Sep
9
revised Computability of infinite-dimensional vector space
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Sep
9
comment Computability of infinite-dimensional vector space
@EmilJeřábek: that's the boring case. The interesting case is when you throw in completeness, say an infinite-dimensional Hilbert space or a Banach space.
Sep
9
answered Computability of infinite-dimensional vector space
Sep
6
comment How to analyze the quality of data definition language?
Ok, to be more constructive: I think it would be better to rephrase the question as a reference request. State a specific problem (such as "how to analyze the efficiency of various data definition languages in practice") and see what references you get. The way the question is stated now just asks for people's opinions.
Sep
6
comment How to analyze the quality of data definition language?
What are you asking, precisely? The question in the title is too unspecified, and in any case is not research-level.
Sep
3
revised Call-by-push-value's denotational semantics of “thunk diverge”
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Sep
3
comment Call-by-push-value's denotational semantics of “thunk diverge”
Sure, an example of that is the coalesced sum.
Sep
2
comment Call-by-push-value's denotational semantics of “thunk diverge”
Identifying all the least elements is a bit drastic. It would turn the predomain of natural numbers, which is flat, into a signleton. When turning a predomain into a domain we should seek an adjoint tothe forgetful functor. Lifting is such an adjoint.
Sep
2
answered Call-by-push-value's denotational semantics of “thunk diverge”
Aug
30
comment What is necessary and/or sufficient requirement for a subring of a field to be computable?
In these sorts of questions I find that the OP often does not really know what it means for a structure to be computable (present company excluded, of course). I think part of the problem is that people know too little about computability on mathematical structure to be even able to ask the question. For instance, this question seems to ask what might be some algebraic conditions on a ring to make it computable. The answer is: without further restrictions (such as "equality must be decidable") every ring can be equipped with a computable structure, albeit the trivial one.
Aug
29
awarded  Nice Answer