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# eq_t(?X, ?Y, +MC)

Tentative value implementation of $=/2 arithmetic equality constraint
*X*
- Expression containing tentative variables
*Y*
- Expression containing tentative variables
*MC*
- A monitored_constraint descriptor

## Description

Tentative value implementation of equality constraint.

The violatedness of the constraint is 0 if the equality holds,
1 otherwise.

The following declaration is in effect, meaning that eq_t/3
is used whenever $= /2 is added to a constraint set:

:- eq_t/3 tent_implements $= /2.

### Modes and Determinism

## Examples

?- [X, Y] tent_set [3, 4], CS :~ (X $= Y).
X = X{3 -> 0}
Y = Y{4 -> 0}
CS = constraint_set(TotalVio{1 -> 0}, ...)
There is 1 delayed goal.
Yes (0.00s cpu)
?- [X, Y] tent_set [3, 3], CS :~ (X $= Y).
X = X{3 -> 0}
Y = Y{3 -> 0}
CS = constraint_set(TotalVio{0 -> 0}, ...)
There is 1 delayed goal.
Yes (0.00s cpu)

## See Also

alldifferent_t / 2, alldifferent_t / 3, neq_t / 3, tentative : tent_implements / 2