** suivant:** GCD of two polynomials
** monter:** Arithmetic and polynomials
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##

GCD of two polynomials with Euclide algorithm: `gcd`

`gcd` denotes the gcd (greatest common divisor) of two polynomials
(or of a list of polynomials or of a sequence of polynomials)
(see also 1.6.2 for GCD of integers).
**Examples**

Input :

`gcd(x``^`

2+2*x+1,x`^`

2-1)

Output :
`x+1 `

Input :
`gcd(x``^`

2-2*x+1,x`^`

3-1,x`^`

2-1,x`^`

2+x-2)

or
`gcd([x``^`

2-2*x+1,x`^`

3-1,x`^`

2-1,x`^`

2+x-2])

Output :
`x-1`

For polynomials with modular coefficients, input e.g. :

`gcd((x``^`

2+2*x+1) mod 5,(x`^`

2-1) mod 5)

Output :
`x % 5`

Note that :
`gcd(x``^`

2+2*x+1,x`^`

2-1) mod 5

will output :
`1`

since the mod operation is done after the GCD is computed in
[*X*].

giac documentation written by Renée De Graeve and Bernard Parisse