making discontinues function, continues.!
Homework Statement
Given a function g, which is not continuous everywhere and g is increasing. The problem is how to approach to this function to make it continuous.
Homework Equations
The Attempt at a Solution
I am not sure but one way...
Actually I have a function of curvature for some transcendental curve. and this curve considered as a coxeter group generated by the reflections about the normal lines through two adjacent extrema of the curvature function.
and it says that since this function of curvature is always non...
I am confused, because
\langle A, B \rangle = \Big\langle \left( \begin{matrix} i & 0 \\ 0 & -i \end{matrix} \right) \left( \begin{matrix} 0 & 1 \\ 1 & 0 \end{matrix} \right)\Big\rangle = \left( \begin{matrix} 0 & i \\ -i & 0 \end{matrix} \right) right?
and this is just an element of...
\langle A, B \rangle = \left( \begin{matrix} 0 & i \\ -i & 0 \end{matrix} \right) and det(<A,B>)=-1, hence det(<A,B>) in GL_2(\mathbb{C}). right?
on the other hand, if we want to show \langle A, B \rangle generated by A and B,
we need to show that A and B are linear independent ?
Homework Statement
A= \left( \begin{matrix}
i & 0 \\
0 &-i
\end{matrix} \right)
, B= \left( \begin{matrix}
0 & 1 \\
1 & 0
\end{matrix} \right)
\\
Show that \langle A, B \rangle is subgroup of GL_2(\mathbb{C}). And Show that \langle A, B \rangle generated by A and B, and order of...
Homework Statement
F(\mathbb{Q},\mathbb{R}) is the set of maps from \mathbb{Q} to \mathbb{R}. Then show that F(\mathbb{Q},\mathbb{R}) and \mathbb{R} have same potency (cardinal number?)..
Homework Equations
The Attempt at a Solution
I am no tsure but I think I need to...
Ok. I think; we have \mathbb{R}= \bigcup\limits_{q \in \mathbb{Q}} f^{-1}(q), and we suppose that for all q in Q , f^{-1}(q) finite, then union would be countable but R is uncountable so contradiction... right?
I didn't understand clearly but ;
for all q \in \mathbb{Q}, we suppose all the sets, f^{-1}(q) are finite. That means, every element of \mathbb{R} is one of these sets, f^{-1}(q) ...right?
infinite set means ; we can't find 1-1 correspondence between the set {1,...,n} and f^{-1}(q) , here f^{-1}(q) has n elements.
So, can we say f^{-1}(q) is uncountable then we can't find 1-1 correspondence between the set {1,...,n}...?
[b] infinite set [b]
Homework Statement
f: \mathbb{R} \rightarrow \mathbb{Q} ,
show that there is a q \in \mathbb{Q} st. f^{-1}(q) is infinite set in \mathbb{R}.
Homework Equations
The Attempt at a Solution
how can we show that is true?