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op_intersect                                                     (Lib)
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op_intersect : ('a -> 'a -> bool) -> 'a list -> 'a list -> 'a list

SYNOPSIS
Computes the intersection of two ‘sets’.

KEYWORDS
list, set.

DESCRIBE
{op_intersect eq l1 l2} returns a list consisting of those
elements of {l1} that are {eq} to some element in {l2}.

FAILURE
Fails if an application of {eq} fails.

EXAMPLE

- op_intersect aconv [Term `\x:bool.x`, Term `\x y. x /\ y`]
                     [Term `\y:bool.y`, Term `\x y. x /\ z`];
> val it = [`\x. x`] : term list




COMMENTS
The order of items in the list returned by {op_intersect} is not dependable.

A high-performance implementation of finite sets may be found in
structure {HOLset}.

There is no requirement that {eq} be recognizable as a kind of
equality (it could be implemented by an order relation, for example).

SEEALSO
Lib.intersect, Lib.op_mem, Lib.op_insert, Lib.op_mk_set, Lib.op_union,
Lib.op_U, Lib.op_set_diff.

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