91,220 reputation
4122241
bio website henning.makholm.net
location Copenhagen, Denmark
age 41
visits member for 3 years, 4 months
seen 24 mins ago

I'm a computer scientist by training (Ph.D. in programming language technology, 2003), currently working in industry. Real mathematics is more of a hobby.

In general, don't assume I necessarily know what I'm talking about, unless it's about computer science or formal logic. I dabble in various other fields that I've never taken courses in, mostly just by extrapolating from Wikipedia.


1h
revised Pebble Problem Maximum$=\big\lceil \log_3(n)\big\rceil$?
remove spurious \displaystyle in title
18h
awarded  Nice Answer
20h
awarded  Guru
21h
revised Inverse of a set, possible?
added 301 characters in body
21h
answered Inverse of a set, possible?
2d
comment How do you find the square root of a binomial?
Now I'm just worried that the word salad in the old-title-cum-first-paragraph is some kind of indication that the question is from an ongoing contest or exam ...
2d
comment What happens to the angles of an isosceles triangle if one vertex is at infinity?
Projective geometry can be made quite rigorous. Unfortunately angle measure is not a projective invariant, so projective geometry is not really an answer to this question.
2d
comment How do you find the square root of a binomial?
What the deuce does that question title even mean?
2d
answered Why not define $|v| = -1$?
2d
awarded  Constituent
Dec
19
comment Algorithm for vector space transformation
@Niskazhu: I'm pretty sure that is explained in painstaking detail on the pages in the book that come before the exercise.
Dec
19
comment distribution probability question involving binary functions for certain n<2^10
@MathyPerson: I don't get why you're subtracting 9, 8, 7, and so forth.
Dec
19
comment distribution probability question involving binary functions for certain n<2^10
@MathyPerson: "...(the absolute maximum # of bits), it would be..."
Dec
19
comment distribution probability question involving binary functions for certain n<2^10
@MathyPerson: Which "it"? My answer to the original question is still $\binom{10}{3}$.
Dec
19
revised Is the preimage of a bounded set also bounded?
better example after comment exchange
Dec
19
comment distribution probability question involving binary functions for certain n<2^10
@MathyPerson: The 00012 example is in decimal, i.e. the usual everyday base-ten. It was just meant to show that adding leading zeroes is not something specific to binary.
Dec
19
comment Is the preimage of a bounded set also bounded?
@PhoemueX: That is still not injective: You get $f(\frac12)=f(2)=\frac 25$. On the other hand $\frac{x}{1+|x|}$ would work, if the tanh offends you.
Dec
19
answered Is the preimage of a bounded set also bounded?
Dec
19
comment Help with proposition whether it's true or false
@Mr.H123: Then you're looking at $2\ne 2\Rightarrow 2=0$, which is true because the antecedent is false.
Dec
19
comment Where does this definition for the free variables of a formula come from?
@user99865: Ignoring quantifiers (which cannot appear in terms) the free variables in a formula are simply all the variables that appear anywhere in the formula. So if the formula looks like $t_1=t_2$, and $t_1$ and $t_2$ are terms, then the variables that appear anywhere are those that appear in $t_1$ together with those that appear in $t_2$. So, for example for the concrete formula $f(x,y)=g(x,z)$, the free variables are $\{x,y,z\}$ -- just all the variables.