disco> {1,2,3} intersect {2,4,7,3}
{2, 3}
disco> {1,2,3} intersection {2,4,7,3}
Error: the expression
  {1, 2, 3}
must have both a function type and also the incompatible type
  Set(a).
https://disco-lang.readthedocs.io/en/latest/reference/notcon.html
disco> {1,2,3} intersect {4,5}
{}
disco> {1,2,3} union {4,5}
{1, 2, 3, 4, 5}
disco> {1,2,3} union {2,3,5}
{1, 2, 3, 5}
disco> {1,2,3} - {2,3,5}
Error: values of type Set(a1) cannot be subtracted.
https://disco-lang.readthedocs.io/en/latest/reference/not-qual.html
disco> {1,2,3} \ {2,3,5}
{1}
disco> {1,2,3} difference {2,3,5}
Error: the expression
  {1, 2, 3}
must have both a function type and also the incompatible type
  Set(a).
https://disco-lang.readthedocs.io/en/latest/reference/notcon.html
disco> {1,2,3} \ {2,3,5}
{1}
disco> :doc \
This expression has multiple possible types.  Some examples:
~\~ : Bag(a) × Bag(a) → Bag(a)
~\~ : Set(a) × Set(a) → Set(a)
precedence level 9, left associative

Difference of two sets (or bags).

https://disco-lang.readthedocs.io/en/latest/reference/set-ops.html

disco> :doc union
This expression has multiple possible types.  Some examples:
~union~ : Bag(a) × Bag(a) → Bag(a)
~union~ : Set(a) × Set(a) → Set(a)
Alternative syntax: ~∪~
precedence level 9, left associative

Union of two sets (or bags).

https://disco-lang.readthedocs.io/en/latest/reference/set-ops.html
https://disco-lang.readthedocs.io/en/latest/reference/symbols.html

disco> {x | x in {0..10}, y in {0 .. 10}, x < y}
{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
disco> {(x,y) | x in {0..10}, y in {0 .. 10}, x < y}
{(0, 1), (0, 2), (0, 3), (0, 4), (0, 5), (0, 6), (0, 7), (0, 8), (0, 9), (0, 10), (1, 2), (1, 3), (1, 4), (1, 5), (1, 6), (1, 7), (1, 8), (1, 9), (1, 10), (2, 3), (2, 4), (2, 5), (2, 6), (2, 7), (2, 8), (2, 9), (2, 10), (3, 4), (3, 5), (3, 6), (3, 7), (3, 8), (3, 9), (3, 10), (4, 5), (4, 6), (4, 7), (4, 8), (4, 9), (4, 10), (5, 6), (5, 7), (5, 8), (5, 9), (5, 10), (6, 7), (6, 8), (6, 9), (6, 10), (7, 8), (7, 9), (7, 10), (8, 9), (8, 10), (9, 10)}