AND_EL_CONV

listLib.AND_EL_CONV : conv

Computes by inference the result of taking the conjunction of the elements of a boolean list.

For any object language list of the form “[x1;x2;...;xn]”, where x1, x2, …, xn are boolean expressions, the result of evaluating

   AND_EL_CONV “AND_EL [x1;x2;...;xn]”

is the theorem

   |- AND_EL [x1;x2;...;xn] = b

where b is either the boolean constant that denotes the conjunction of the elements of the list, or a conjunction of those xi that are not boolean constants.

Example

> listLib.AND_EL_CONV “AND_EL [T;F;F;T]”;
val it = ⊢ AND_EL [T; F; F; T] ⇔ F: thm

> listLib.AND_EL_CONV “AND_EL [T;T;T]”;
val it = ⊢ AND_EL [T; T; T] ⇔ T: thm

> listLib.AND_EL_CONV “AND_EL [T;x;y]”;
val it = ⊢ AND_EL [T; x; y] ⇔ x ∧ y: thm

> listLib.AND_EL_CONV “AND_EL [x;F;y]”;
val it = ⊢ AND_EL [x; F; y] ⇔ F: thm

Failure

AND_EL_CONV tm fails if tm is not of the form described above.