Is $x_i(t+1)=|S_i(t)|^-1sum_jin S_i(t) x_jquad i=1,dots,n$ a linear system?

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I have $x_i(t)inmathbb [0,1]$ for $i=1,dots, n$, with $n,tinmathbb N$. Let us consider the set
$$S_i(t):=left1leq jleq n Bigl$$
I'm trying to understand if the following system
$$x_i(t+1)=|S_i(t)|^-1sum_jin S_i(t) x_jquad i=1,dots,n$$
(where $|cdot|$ for a finite set denotes the number of elements) is linear or not in $x_1,dots,x_n$.



What do you think?







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  • Is your $t$ a parameter, where does it come from? Also, what do you mean with $x_i(t)$?
    – zzuussee
    Jul 27 at 19:31






  • 3




    Unless I'm misunderstanding your definition of linear, I don't see how this could possibly be linear, given that $|S_i(t)|$ isn't even continuous in $x_i$. Suppose you have $x_1=0$ and $x_2=1/4$. Then $|S_1(t)| = 2$. Now translate $x_2rightarrow x_2+1$. Then $|S_1(t)|=1$.
    – Alex R.
    Jul 27 at 19:37










  • @AlexR. Thank you, but I don't understand why your example would prove the nonlinearity of the system...
    – Mark
    Jul 28 at 9:48










  • @zzuussee, I'm sorry I've updated the post
    – Mark
    Jul 28 at 9:48














up vote
1
down vote

favorite












I have $x_i(t)inmathbb [0,1]$ for $i=1,dots, n$, with $n,tinmathbb N$. Let us consider the set
$$S_i(t):=left1leq jleq n Bigl$$
I'm trying to understand if the following system
$$x_i(t+1)=|S_i(t)|^-1sum_jin S_i(t) x_jquad i=1,dots,n$$
(where $|cdot|$ for a finite set denotes the number of elements) is linear or not in $x_1,dots,x_n$.



What do you think?







share|cite|improve this question





















  • Is your $t$ a parameter, where does it come from? Also, what do you mean with $x_i(t)$?
    – zzuussee
    Jul 27 at 19:31






  • 3




    Unless I'm misunderstanding your definition of linear, I don't see how this could possibly be linear, given that $|S_i(t)|$ isn't even continuous in $x_i$. Suppose you have $x_1=0$ and $x_2=1/4$. Then $|S_1(t)| = 2$. Now translate $x_2rightarrow x_2+1$. Then $|S_1(t)|=1$.
    – Alex R.
    Jul 27 at 19:37










  • @AlexR. Thank you, but I don't understand why your example would prove the nonlinearity of the system...
    – Mark
    Jul 28 at 9:48










  • @zzuussee, I'm sorry I've updated the post
    – Mark
    Jul 28 at 9:48












up vote
1
down vote

favorite









up vote
1
down vote

favorite











I have $x_i(t)inmathbb [0,1]$ for $i=1,dots, n$, with $n,tinmathbb N$. Let us consider the set
$$S_i(t):=left1leq jleq n Bigl$$
I'm trying to understand if the following system
$$x_i(t+1)=|S_i(t)|^-1sum_jin S_i(t) x_jquad i=1,dots,n$$
(where $|cdot|$ for a finite set denotes the number of elements) is linear or not in $x_1,dots,x_n$.



What do you think?







share|cite|improve this question













I have $x_i(t)inmathbb [0,1]$ for $i=1,dots, n$, with $n,tinmathbb N$. Let us consider the set
$$S_i(t):=left1leq jleq n Bigl$$
I'm trying to understand if the following system
$$x_i(t+1)=|S_i(t)|^-1sum_jin S_i(t) x_jquad i=1,dots,n$$
(where $|cdot|$ for a finite set denotes the number of elements) is linear or not in $x_1,dots,x_n$.



What do you think?









share|cite|improve this question












share|cite|improve this question




share|cite|improve this question








edited Jul 28 at 9:45
























asked Jul 27 at 19:02









Mark

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  • Is your $t$ a parameter, where does it come from? Also, what do you mean with $x_i(t)$?
    – zzuussee
    Jul 27 at 19:31






  • 3




    Unless I'm misunderstanding your definition of linear, I don't see how this could possibly be linear, given that $|S_i(t)|$ isn't even continuous in $x_i$. Suppose you have $x_1=0$ and $x_2=1/4$. Then $|S_1(t)| = 2$. Now translate $x_2rightarrow x_2+1$. Then $|S_1(t)|=1$.
    – Alex R.
    Jul 27 at 19:37










  • @AlexR. Thank you, but I don't understand why your example would prove the nonlinearity of the system...
    – Mark
    Jul 28 at 9:48










  • @zzuussee, I'm sorry I've updated the post
    – Mark
    Jul 28 at 9:48
















  • Is your $t$ a parameter, where does it come from? Also, what do you mean with $x_i(t)$?
    – zzuussee
    Jul 27 at 19:31






  • 3




    Unless I'm misunderstanding your definition of linear, I don't see how this could possibly be linear, given that $|S_i(t)|$ isn't even continuous in $x_i$. Suppose you have $x_1=0$ and $x_2=1/4$. Then $|S_1(t)| = 2$. Now translate $x_2rightarrow x_2+1$. Then $|S_1(t)|=1$.
    – Alex R.
    Jul 27 at 19:37










  • @AlexR. Thank you, but I don't understand why your example would prove the nonlinearity of the system...
    – Mark
    Jul 28 at 9:48










  • @zzuussee, I'm sorry I've updated the post
    – Mark
    Jul 28 at 9:48















Is your $t$ a parameter, where does it come from? Also, what do you mean with $x_i(t)$?
– zzuussee
Jul 27 at 19:31




Is your $t$ a parameter, where does it come from? Also, what do you mean with $x_i(t)$?
– zzuussee
Jul 27 at 19:31




3




3




Unless I'm misunderstanding your definition of linear, I don't see how this could possibly be linear, given that $|S_i(t)|$ isn't even continuous in $x_i$. Suppose you have $x_1=0$ and $x_2=1/4$. Then $|S_1(t)| = 2$. Now translate $x_2rightarrow x_2+1$. Then $|S_1(t)|=1$.
– Alex R.
Jul 27 at 19:37




Unless I'm misunderstanding your definition of linear, I don't see how this could possibly be linear, given that $|S_i(t)|$ isn't even continuous in $x_i$. Suppose you have $x_1=0$ and $x_2=1/4$. Then $|S_1(t)| = 2$. Now translate $x_2rightarrow x_2+1$. Then $|S_1(t)|=1$.
– Alex R.
Jul 27 at 19:37












@AlexR. Thank you, but I don't understand why your example would prove the nonlinearity of the system...
– Mark
Jul 28 at 9:48




@AlexR. Thank you, but I don't understand why your example would prove the nonlinearity of the system...
– Mark
Jul 28 at 9:48












@zzuussee, I'm sorry I've updated the post
– Mark
Jul 28 at 9:48




@zzuussee, I'm sorry I've updated the post
– Mark
Jul 28 at 9:48















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