Normally, the MATCH function receives a single lookup value, and returns a single match if any. In this case, however, we are giving MATCH an array for lookup value, so it will return an array of results, one per element in the lookup array. MATCH is configured for "exact match". If a match isn't found, MATCH will return the #N/A error. After match runs, it returns have something like this:
We take advantage of this by using the ISNA function to test for any #N/A errors.
After ISNA, we have:
We use the double negative (double unary) operator to convert TRUE FALSE values to ones and zeros, which gives us this:
SUMPRODUCT then sums the elements in the array, and the result is compared to zero for force a TRUE or FALSE result.