cihan's profile - activity

This works! Thanks!

I am not quite sure what you mean, since $\gcd(1275,1309)=17$.

I have a list $L$ of ordered pairs $(n,m)$ where $n$ and $m$ are integers. I would like to know which elements $(n,m)$ in $L$ satisfy the property that $\gcd(n+i,m+j) \neq 1$ for $i =-1,0,1$ and $j =-1,0,1.$ For example the point $(55,21)$ has this property since $[(55+i,21+j) ] = [(54,20),(54,21),(54,22),(55,20),(55,21),(55,22),(56,20),(56,21),(56,22)].$ I have tried the following : for (n,m) in L: for i in range(-1,2): for j in range(-1,2): if gcd(n+i,m+j)!=1: print(n,m) which returns any point with $gcd =1$ which is not what I want. Thanks very much for your help!

That is probably true since I am very new to Python and to programming in general. The code I used is a bit lengthy so I will try to explain in words what I need. I basically want Sage to assume V[i]=V[7-i] for i in range(j) when solving the system. I tried to use the assume command but wasnt successful.

Thanks, but this is not what I was looking for. I would like sage to assume x=d, y=c and so on when solving the system.

I have a variables list which I use to construct a system of linear equations then I use sage to solve this system. Before I use the solve command I like to equate some of the variables in the list. For example if V is the following list var('x,y,z,w,a,b,c,d') V2=[x,y,z,w,a,b,c,d]

I would like to assignV[i]=V[7-i] for i in [0..3]. When I do this I get invalid syntax error. I know that I could easily set x=d, y=c and so on but this is not feasible when the list has too many items in it. Thank you for your help!

Thanks very much for your help! it works.

I would like to define a doubly indexed sum. Below is what I did:

V=list(var(','.join(['a_%d%d' % (i,n) for i in [0..5] for n in [0..5]])))
sum(a_in*binomial(5,i)*binomial(5,n) for i in [0..5] for n in [0..5])

I get the global name 'a_' is not defined error. I tried this when there is only one index and it works, but doesnt seem to work for double index. Can anyone help me with this?