i1 : same {1, 1, 1, 1}
o1 = true
|
i2 : same {1, 2, 1, 1}
o2 = false
|
The comparison is done with "===", which is quick, but not always intuitive. Here is a simple example of what can go wrong:
i3 : R = QQ[x,y,z]; |
i4 : L = {gcd{x,y}, x/x, 1}
o4 = {1, 1, 1}
o4 : List
|
i5 : same L o5 = false |
We can see the problem by asking Macaulay2 to display the class of each element of L. (Or use the function uniform, which returns whether or not the elements of a list are all of the same class.)
i6 : apply(L, class)
o6 = {R, frac R, ZZ}
o6 : List
|
i7 : uniform L o7 = false |
The first 1 is an element of the ring R, the second 1 is an element of the fraction field of R, and the third 1 is an integer. Thus Macaulay2 thinks of these three elements as being pairwise unequal, with respect to the operator "===".
The object same is a function closure.