Skip to main content
Punctuation, while this is on the front page
Source Link
LSpice
  • 12.9k
  • 4
  • 45
  • 69

B-topological ring that is not semi topological-topological?

A topological space $A$ that is also a ring with operations '+'$+$ and '.' where $ A\times A$ carries product topology$.$, is a semi-topological ring if the mappings $$a_1: A\times A \to A\ \text{such that}\ (x,y)\to x+y$$ , $$a_2: A \to A\ \text{such that}\ x\to -x$$ and \begin{gather*} a_1: A\times A \to A\text{ such that }(x,y)\to x+y, \\ a_2: A \to A\text{ such that }x\to -x \end{gather*} and $$a_3: A \to A\ \text{such that}\ (x,y) \to x.y$$$$a_3: A \to A\text{ such that }(x,y) \to x.y$$ are semi-continuous where $ A\times A$ carries product topology.

A topological space $A$ that is also a ring with operations '+'$+$ and '.' where $ A\times A$ carries product topology$.$, is a B-topological ring if the mappings $$a_1: A\times A \to A\ \text{such that}\ (x,y)\to x+y$$ , $$a_2: A \to A\ \text{such that}\ x\to -x$$ and\begin{gather*} a_1: A\times A \to A\text{ such that }(x,y)\to x+y, \\ a_2: A \to A\text{ such that }x\to -x \end{gather*} and $$a_3: A \to A\ \text{such that}\ (x,y) \to x.y$$$$a_3: A \to A\text{ such that }(x,y) \to x.y$$ are b-continuous where $ A\times A$ carries product topology.

whereWhere,

A function $f:X \to Y$ from topological space $X$ to topological space $Y$ is said to be b-continuous (semi continuous-continuous) if for each $x\in X$ and each open set $U \subset Y$ containing $f(x)$ there exists a b-open (semi-open) set $V \subset X$ containing $x$ such that $f(V) \subset U$.

A$\DeclareMathOperator\Int{Int}\DeclareMathOperator\cl{cl}$A set $B$ is called b-open if $B \subset Int(cl(B)) \cup cl(Int(B))$$B \subset \Int(\cl(B)) \cup \cl(\Int(B))$ and $S$ is semi open-open if $S \subset cl(Int(S))$$S \subset \cl(\Int(S))$.

Clearly, Topologicaltopological rings $\implies$ semi-topological rings $\implies$ B-topological rings but not conversely.

After all these definitions I seek a B-topological ring that is not semi-topological. I already have other counterexamples but this one I have no idea about.

B-topological ring that is not semi topological?

A topological space $A$ that is also a ring with operations '+' and '.' where $ A\times A$ carries product topology, is a semi-topological ring if the mappings $$a_1: A\times A \to A\ \text{such that}\ (x,y)\to x+y$$ , $$a_2: A \to A\ \text{such that}\ x\to -x$$ and $$a_3: A \to A\ \text{such that}\ (x,y) \to x.y$$ are semi-continuous.

A topological space $A$ that is also a ring with operations '+' and '.' where $ A\times A$ carries product topology, is a B-topological ring if the mappings $$a_1: A\times A \to A\ \text{such that}\ (x,y)\to x+y$$ , $$a_2: A \to A\ \text{such that}\ x\to -x$$ and $$a_3: A \to A\ \text{such that}\ (x,y) \to x.y$$ are b-continuous.

where,

A function $f:X \to Y$ from topological space $X$ to topological space $Y$ is said to be b-continuous (semi continuous) if for each $x\in X$ and each open set $U \subset Y$ containing $f(x)$ there exists a b-open (semi-open) set $V \subset X$ containing $x$ such that $f(V) \subset U$.

A set $B$ is called b-open if $B \subset Int(cl(B)) \cup cl(Int(B))$ and $S$ is semi open if $S \subset cl(Int(S))$

Clearly, Topological rings $\implies$ semi-topological rings $\implies$ B-topological rings but not conversely.

After all these definitions I seek a B-topological ring that is not semi-topological. I already have other counterexamples but this one I have no idea about.

B-topological ring that is not semi-topological?

A topological space $A$ that is also a ring with operations $+$ and $.$, is a semi-topological ring if the mappings \begin{gather*} a_1: A\times A \to A\text{ such that }(x,y)\to x+y, \\ a_2: A \to A\text{ such that }x\to -x \end{gather*} and $$a_3: A \to A\text{ such that }(x,y) \to x.y$$ are semi-continuous where $ A\times A$ carries product topology.

A topological space $A$ that is also a ring with operations $+$ and $.$, is a B-topological ring if the mappings \begin{gather*} a_1: A\times A \to A\text{ such that }(x,y)\to x+y, \\ a_2: A \to A\text{ such that }x\to -x \end{gather*} and $$a_3: A \to A\text{ such that }(x,y) \to x.y$$ are b-continuous where $ A\times A$ carries product topology.

Where,

A function $f:X \to Y$ from topological space $X$ to topological space $Y$ is said to be b-continuous (semi-continuous) if for each $x\in X$ and each open set $U \subset Y$ containing $f(x)$ there exists a b-open (semi-open) set $V \subset X$ containing $x$ such that $f(V) \subset U$.

$\DeclareMathOperator\Int{Int}\DeclareMathOperator\cl{cl}$A set $B$ is called b-open if $B \subset \Int(\cl(B)) \cup \cl(\Int(B))$ and $S$ is semi-open if $S \subset \cl(\Int(S))$.

Clearly, topological rings $\implies$ semi-topological rings $\implies$ B-topological rings but not conversely.

After all these definitions I seek a B-topological ring that is not semi-topological. I already have other counterexamples but this one I have no idea about.

Bumped by Community user
Bumped by Community user
Bumped by Community user
Notice removed Draw attention by CommunityBot
Bounty Ended with no winning answer by CommunityBot
Notice added Draw attention by Bhaskar Vashishth
Bounty Started worth 150 reputation by Bhaskar Vashishth
deleted 6 characters in body
Source Link

A topological space $A$ that is also a ring with operations '+' and '.' where $ A\times A$ carries product topology, is a semi-topological ring if the mappings $$a_1: A\times A \to A\ \text{such that}\ (x,y)\to x+y$$ , $$a_2: A \to A\ \text{such that}\ x\to -x$$ and $$a_3: A \to A\ \text{such that}\ (x,y) \to x.y$$ are semi-continuous.

A topological space $A$ that is also a ring with operations '+' and '.' where $ A\times A$ carries product topology, is a B-topological ring if the mappings $$a_1: A\times A \to A\ \text{such that}\ (x,y)\to x+y$$ , $$a_2: A \to A\ \text{such that}\ x\to -x$$ and $$a_3: A \to A\ \text{such that}\ (x,y) \to x.y$$ are b-continuous.

where,

A function $f:X \to Y$ from topological space $X$ to topological space $Y$ is said to be b-continuous (semi continuous) if for each $x\in X$ and each open set $U \subset Y$ containing $f(x)$ there exists a b-open (semi-open) set $V \subset X$ containing $x$ such that $f(V) \subset U$.

A set $B$ is called b-open if $B \subset Int(cl(B)) \cup cl(Int(B))$ and $S$ is semi continuousopen if $S \subset cl(Int(S))$

Clearly, Topological rings $\implies$ semi-topological rings $\implies$ B-topological rings but not conversely.

After all these definitions I seek a B-topological ring that is not semi-topological. I already have other counterexamples but this one I have no idea about.

A topological space $A$ that is also a ring with operations '+' and '.' where $ A\times A$ carries product topology, is a semi-topological ring if the mappings $$a_1: A\times A \to A\ \text{such that}\ (x,y)\to x+y$$ , $$a_2: A \to A\ \text{such that}\ x\to -x$$ and $$a_3: A \to A\ \text{such that}\ (x,y) \to x.y$$ are semi-continuous.

A topological space $A$ that is also a ring with operations '+' and '.' where $ A\times A$ carries product topology, is a B-topological ring if the mappings $$a_1: A\times A \to A\ \text{such that}\ (x,y)\to x+y$$ , $$a_2: A \to A\ \text{such that}\ x\to -x$$ and $$a_3: A \to A\ \text{such that}\ (x,y) \to x.y$$ are b-continuous.

where,

A function $f:X \to Y$ from topological space $X$ to topological space $Y$ is said to be b-continuous (semi continuous) if for each $x\in X$ and each open set $U \subset Y$ containing $f(x)$ there exists a b-open (semi-open) set $V \subset X$ containing $x$ such that $f(V) \subset U$.

A set $B$ is called b-open if $B \subset Int(cl(B)) \cup cl(Int(B))$ and $S$ is semi continuous if $S \subset cl(Int(S))$

Clearly, Topological rings $\implies$ semi-topological rings $\implies$ B-topological rings but not conversely.

After all these definitions I seek a B-topological ring that is not semi-topological. I already have other counterexamples but this one I have no idea about.

A topological space $A$ that is also a ring with operations '+' and '.' where $ A\times A$ carries product topology, is a semi-topological ring if the mappings $$a_1: A\times A \to A\ \text{such that}\ (x,y)\to x+y$$ , $$a_2: A \to A\ \text{such that}\ x\to -x$$ and $$a_3: A \to A\ \text{such that}\ (x,y) \to x.y$$ are semi-continuous.

A topological space $A$ that is also a ring with operations '+' and '.' where $ A\times A$ carries product topology, is a B-topological ring if the mappings $$a_1: A\times A \to A\ \text{such that}\ (x,y)\to x+y$$ , $$a_2: A \to A\ \text{such that}\ x\to -x$$ and $$a_3: A \to A\ \text{such that}\ (x,y) \to x.y$$ are b-continuous.

where,

A function $f:X \to Y$ from topological space $X$ to topological space $Y$ is said to be b-continuous (semi continuous) if for each $x\in X$ and each open set $U \subset Y$ containing $f(x)$ there exists a b-open (semi-open) set $V \subset X$ containing $x$ such that $f(V) \subset U$.

A set $B$ is called b-open if $B \subset Int(cl(B)) \cup cl(Int(B))$ and $S$ is semi open if $S \subset cl(Int(S))$

Clearly, Topological rings $\implies$ semi-topological rings $\implies$ B-topological rings but not conversely.

After all these definitions I seek a B-topological ring that is not semi-topological. I already have other counterexamples but this one I have no idea about.

edited title
Link

B-topological ring that is not semi continuoustopological?

Source Link
Loading