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Enthusiastic about computer graphics, vintage computing and hardware.

Niklas Rosencrantz (Stockholm, Sweden)


Jul
9
awarded  Famous Question
Jul
2
awarded  Curious
Jun
22
comment Could the birthday paradox be interpreted also about deaths?
The actual situation was that I mentioned the birthday paradox, and a guy said that he went to a funeral and noticed a graveyard where 3/10 deaths where the same date and I think it's perhaps not an instance of the birthday/death probability but rather an instance of locality in time and space, or some other explanation. So I could look at statistics from tombstones for real data about what we spoke about, if we can take the probability from the birthday paradox and expect it to say something about tombstone and graveyard dates in the real world.
Jun
22
revised Could the birthday paradox be interpreted also about deaths?
edited tags
Jun
22
comment Could the birthday paradox be interpreted also about deaths?
Thank you for the info. I studied Markov chains that perhaps could model births and deaths processes, but I couldn't take for granted that they are distributed same way. For example: If an asteroid destroys earth on a particular day and everybody dies the same day, then I suppose that it would make a difference.
Jun
22
accepted Could the birthday paradox be interpreted also about deaths?
Jun
22
asked Could the birthday paradox be interpreted also about deaths?
Jun
19
revised What is the hat number problem?
added 3 characters in body
Jun
9
awarded  Popular Question
May
19
comment Would a set of tensors be an algebraic group closed under some operation?
Can we write 2 tensors as 1 tensor of tensors (similar to how we can make a superset of 2 sets)? Could the basics of rotation, translation and scaling make a good example? If the 2 matrices are tensors, can I make a matrix of matrics and still keep it a tensor of 2 or more tensors? In an application we got 3 or more matrices but I have no proof why there must be no less than 3 matrices (rotation matrix, translation matrix and scaling matrix).
May
19
accepted Would a set of tensors be an algebraic group closed under some operation?
May
19
comment Would a set of tensors be an algebraic group closed under some operation?
According to Norman Biggs book discrete mathematics, a group could be a mathematical object with some operation and I think I remember an interesting example with a triangle with a rotation operation (or numbers with addition). Then I read about the kronecker delta and then I'm not sure whether we can write 2 tensors as 1 tensor of tensors.
May
19
comment Would a set of tensors be an algebraic group closed under some operation?
Thank you for providing details. I thought there was a (conceptual) difference between how to make a statement about "all tensors" and "every tensor" since what's true for every tensor might not be true for "all tensors", which would be a set or some other way to write many tensors at once. I heard that a matrix of matrices could be a tensor, so could there be a tensor of tensors instead and therefore all tensors can be written as one tensor of tensors?
May
19
awarded  Yearling
May
19
asked Would a set of tensors be an algebraic group closed under some operation?
Apr
7
revised Does law of excluded middle prove itself?
added 189 characters in body
Apr
4
comment Is there a simple example of how the law of the excluded middle can be inapplicable?
Similarly to statistical testing where rejecting a hypothesis is not the same as accepting the alternative hypothesis.
Apr
4
comment Is there a simple example of how the law of the excluded middle can be inapplicable?
@dtldarek That's interesting. A practical problem I had was to model and test for "locked" XOR "unlocked" where the alternatives should be mutually exclusive and therefore we could model that with a boolean variable, but if I test an entity for the value of unlocked and find that it is false that it's unlocked, that doesn't guarantee that the system is consistent and that the entity doesn't get reported as both locked and unlocked since that is testing the system's consistency that entities don't get inconsistent values like a user account that is locked and unlocked at the same time.
Apr
4
answered Does law of excluded middle prove itself?
Apr
4
revised Is there a simple example of how the law of the excluded middle can be inapplicable?
added 1 characters in body