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Feb
2
comment Linear Algebra book for beginners
I suggest you the online version of a "A First Course in Linear Algebra" by Robert A. Beezer. It is avaiable from linear.ups.edu/download.html and what it is really great is the possibility to use the (free) software "sage" for the examples.
Jan
15
comment “Minimal upper bounds” in a categorical setting
@Eric: That was one of my attempts, but in this case it happens that corproducts do not satisfy this "minimality" (if I am not worng).
Jan
15
revised “Minimal upper bounds” in a categorical setting
added 1 character in body
Jan
15
comment “Minimal upper bounds” in a categorical setting
@Eric: I am asking for a categorical notion of "a minimal upper bound" as oposed to "the minimum upper bound". In particular, the unicity (up to isomorphism) needs to be lost.
Jan
14
asked “Minimal upper bounds” in a categorical setting
Jan
6
revised Number of k-ary monotone maps from 1..n+1 to 1..n+1.
added 1 character in body
Jan
6
comment Number of k-ary monotone maps from 1..n+1 to 1..n+1.
@Random: Thanks. As you have pointed out, Dedekind numbers provide an answer for the case n=1.
Jan
6
revised Number of k-ary monotone maps from 1..n+1 to 1..n+1.
edited body
Jan
6
comment Number of k-ary monotone maps from 1..n+1 to 1..n+1.
@Brian: See the clarification I have added to the question.
Jan
6
revised Number of k-ary monotone maps from 1..n+1 to 1..n+1.
added 371 characters in body
Jan
5
asked Number of k-ary monotone maps from 1..n+1 to 1..n+1.
Jan
4
comment Finite Strong Completeness Theorem for BL logic
Hint: When you assume that $\varphi_1, \ldots, \varphi_n \not \vdash_{BL} \varphi$, use the fact that $\vdash_{BL}$ is strongly complete with respect to the class of all BL-chains. I guess you are aware of this result (it can be "easily" proved using a Lindenbaum-Tarski argument together with the fact that all subdirectly irreducible BL-algebras are chains).
Jan
4
comment Finite Strong Completeness Theorem for BL logic
What are the problems you find when you try to use any of these two embeddability results to provide a direct proof (of the finite strong completeness)?
Dec
31
comment Graded modules/algebras on commutative monoids?
What is the definition of "M-graded abelian group"? Any reference? I wasn't able to find it in a quick google search
Sep
5
comment Is there an algorithm for computing pushouts in $\sf FinSet$?
Two issues: 1) Which environment category are you considering (sets with total functions, finite sets with total functions, etc)? 2) If you know how to calculate coproducts and coequalizers then there is a well known method explaining how to calculate pushouts (and indeed all colimits); a good summary of the method is given in mathoverflow.net/questions/171920/…
Jul
17
comment What is the Best Introduction to Dedekind Cuts?
Why not "Continuity and Irrational Numbers" by Richard Dedekind? It is freely available from gutenberg.org/ebooks/21016 and I am pretty sure you will not find it very demanding.
May
17
comment MTL algebra 'prelinearity' condition etymology
@user: The generation is done in the usual way of universal algebra, which is the HSP theorem. Take a look at en.wikipedia.org/wiki/Universal_algebra#Some_basic_theorems
May
16
comment MTL algebra 'prelinearity' condition etymology
In partial orders, the word "linear" is also used as a synonym of being a total order (i.e., a chain). This is the appropiate sense to understand prelinearity in the MTL setting; the reason is that the variety of MTL algebras (i.e., prelinear FLew algebras) is generated by chains. To sum up, no realtionship with the use of the word "linear" in "Linear Algebras"
Mar
5
comment What technical books should I read to understand clearly Gödel's theorems and their implications for math?
I also suggest the lecture notes "Gödel Without (Too Many) Tears" by the very Peter Smith. They are available from logicmatters.net/igt/godel-without-tears
Feb
18
comment Reference for Algebraic Categories
Look at the book "Algebraic Theories: A Categorical Introduction to General Algebra" by Adamek et al. books.google.es/books?id=siNlAn8Bm30C The book is available from Adamek's web page iti.cs.tu-bs.de/~adamek/algebraic_theories.pdf