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1 vote
0 answers
66 views

Continuity in the uniform operator topology of a map

I have a question concerning the continuity for $t>0$ in the uniform operator topology $L(X)$ of the following map: $$t\mapsto A^\alpha R(t)$$ where A is the infinitesimal generator of an analytic ...
Mathlover's user avatar
2 votes
0 answers
130 views

Friedrichs Inequality

I'm a little confused with the following proof of Friedrichs inequality in Lawson's & Michelsohn's book Spin geometry, page 194, Theorem 5.4. I don't understand why the last inequality, i.e. $$ C(\...
D.Liu's user avatar
  • 21
3 votes
0 answers
65 views

Second order non-instantaneous impulsive evolution equations

The first order linear non-instantaneous impulsive evolution equations is given as; $$u'(t)=Au(t)~~ t\in[s_i,t_{i+1}],\,i\in\mathbb{N_0}:=\{0,1,2,...\}$$ $$u(t_i^+)=(E+B_i)u(t_i^-),\,\,i\in\mathbb{...
avg_ali's user avatar
  • 59
1 vote
1 answer
288 views

A property of one-parameter groups of operators

Let $X$ be a Banach space. We consider the evolution equation: $$x'(t)=Ax(t), \ \ \ \ \ \ \ t\in \mathbb{R},$$ where $A$ is a bounded operator. I know that if $X=\mathbb{R^n}$ and $A$ is a matrix, ...
user144542's user avatar
6 votes
1 answer
964 views

How is Kolmogorov forward equation derived from the theory of semigroup of operators?

In Lamperti's Stochastic Processes, given a time-homogeneous Markov process $X(t), t\geq 0$ with Markov transition kernel $p_t(x,E)$ and state space being a measurable space $(S, \mathcal{F})$, a ...
Tim's user avatar
  • 357
3 votes
2 answers
1k views

Do these kernel functions satisfy the semigroup property?

Define the kernel functions for $a\ge 1$, $$ G_a(t,x) := \frac{C_a t}{t^{1+1/a}+|x|^{1+a}}, \qquad \forall t>0,\: x\in \mathbb{R}\;, $$ where the constant $C_a$ is some normalization constant ...
Anand's user avatar
  • 1,629