Math

Lebesgue Measure
Le 17/05/2010 23:46, W^3 a �crit : In article <921617200.174707.1274112540433.JavaMail.root(a)gallium.mathforum.org>, Maury Barbato<mauriziobarbato(a)aruba.it> wrote: Hello, is there some Lipschitz function f:[a,b]->R such that for some Lebesgue measurable set A, the preimage of A f^(-1)(A) i... 9 Jul 2010 09:26

Conditions for Functions of Many Complex Variables to be Analytic.?
bacle wrote: Could anyone please tell me the conditions for a function from C^n to C^m ( C is the complexes) to be analytic.?. I have looked thru some online sites, and they are too formal; would someone please just say something like wether we need C-Riemann to be satisfied by each variable. Thi... 9 Jul 2010 08:20

I just had a wild idea
What's the name of an integer matrix whose inverse is also an integer matrix? ... 10 Jul 2010 09:25

Jacobian of a projective transformation
Hi, in a paper i am reading, there is the following derivation: Suppose you have a vector v=[x y 1] and a 3x3 real matrix G. They define a "group action" w : SL(3)xP^2 -> P^2. For all G in SL(3), we have that w(G):P^2->P^2 is an automorphism. So, if G=[g11 g12 g13; g21 g22 g23; g31 g32 g33]= [g1; g2; g3] (... 9 Jul 2010 06:09

Convexity of log to sum of exponentials
My question is: the function f(x) = log(x) is concave the function h(z) = log(sum(exp(g_i)) is convex, as long as the functions g_i are convex (the log to a sum of exponentials to convex functions) How is the last true? The outer function log() is concave and nondecreasing, while the inner function is convex. ... 10 Jul 2010 12:43

3SAT - HiLo SAT Solver
The HiLo solver is a resolution based counting solver. It uses DPLL and conflict driven clause learning. Unlike many solvers, HiLo uses a fixed variable order and all learnt clauses are of decision variables. HiLo solvers can start at any position in "assignment space". The Lo solver counts upward and the Hi sol... 9 Jul 2010 21:39

Interested in getting good at math any book recommendations?
Hello, I'm currently enrolled in a local community college and wish to major in Geology. My math skills are not at the level that they should be. My goal is to really understand and get good at math. I have a month or two before i begin fall classes. Once i enrolled at the local community college I was given a... 12 Jul 2010 05:15

Linear algebra question
Given a column vector v is it possible to express, using "traditional" linear algebra operators/notation, the matrix which contains the elements of v along the diagonal, and all other elements zero? I essentially want what Matlab would produce with "diag(v)" but expressed as a matrix/vector equation. Thanks... 9 Jul 2010 09:26

Simplification of natural log
f(x) = -3ln(2 - x). If g(x) = x ^ 2, find, using calculus, the coordinates of any stationary points of (f + g)(x). I get ([2 - 10 ^ (1 / 2)] / 2, 3ln{[10 ^ (1 / 2) - 2] / 3} - 10 ^ (1 / 2) + 7 / 2)) but the answers say ([2 - 10 ^ (1 / 2)] / 2, -3ln{2 - [2 - 10 ^ (1 / 2)] / 2} + 7 / 2 - 10 ^ (1 / 2)). Are the... 10 Jul 2010 06:14

(10i)^n = [10^n]/10i
i=0,1 1/i=10i (10i)^2 = 100i = 10 10/i=100i, (10i)^3 = 1000i =100 Ricapitolando si ha : 10i^1=10i 1 1^1 10i^2=100i 10 1^2 10i^3=1000i 100 1^3 10i^4=10000i 1000 1^4 10i^5=100'000i 10'000 1^5 10i^6=1'000000i 100'000 1^6 10i^7=10'000'000i... 11 Jul 2010 12:40