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### Concatenation of list of variables

Suppose I have three varaibles x,y,z. For pratical reason, I want to define :

varx = var('x y')
varl = var('z')


A problem arrise immediately

type(varx)


returns <class 'tuple'>

when

type(varl)


returns <class 'sage.symbolic.expression.Expression'>. As they are not of the same (i can understand why but it seems a little weird) type, it's not possible to concatenate them. What is strange is that

[varl]


is a list, but

list(varl)


is not because varl is not enumerable. Finaly,

list(varx)+[varl]


do what i was expecting (concatenation), but it was after a long time of essais and error. Could some one explain the logic behind this ?

### Concatenation of list of variables

Suppose I have three varaibles variables x,y,z. For pratical reason, reasons, I want to define :

varx = var('x y')
varl = var('z')


A problem arrise immediately

type(varx)


returns <class 'tuple'>

when

type(varl)


returns <class 'sage.symbolic.expression.Expression'>. As they are not of the same (i can understand why but it seems a little weird) type, it's not possible to concatenate them. What is strange is that

[varl]


is a list, but

list(varl)


is not because varl is not enumerable. Finaly,Finally,

list(varx)+[varl]


do what i I was expecting (concatenation), but it was after a long time of essais and error. Could some one explain the logic behind this ?