## Wednesday, March 20, 2013

### Zalman Shmotkin is not a Mathematician

I just got the following email from Rabbi Zalman Shmotkin
Dear Friend,

Real quick:

What do 191 people in Mozambique, 334 in Bahrain and 4,719 in Japan have in common?

Simple.

They all joined more than one million unique individuals, each of whom who gleaned advice or received inspiration, meaning, community and much more, during this past week at Chabad.org…!

Were he a mathematician, he would have referred to the "more than one million distinct individuals." In mathematics, when you say there is a unique object having a certain property, it means there is only one object with that property. Obviously, there is not a unique person having the property of having visited chabad.org. If you want to assert that n objects have a certain property, and you want to make clear that you didn't count any of those objects twice, you'd say "there are n distinct...."

Consider the statment, "There is one person responsible for cleaning the house for Pesach, the housewife." This statement does not exclude the possibility that the housewife shares the responsibility with someone else. A better way to say it would be "There is a unique person...."

Consider the statement, "There are two people who are responsible for cleaning the house for Pesach: the housewife and the cleaning lady." This statement does not (explicitly) exclude the possibility that the housewife and the cleaning lady are the same person. A better way to say this would be "There are two distinct people...."

1. We're still left with the question of whether the housewife is indeed the cleaning lady or whether they're two individuals. I'd also like an itemized list with their various responsibilities.

2. But every person is unique!

3. Every real number is unique. And even so the solutions to x^2=0 are not unique.

4. Nor is Rabbi Zalman Shmotkin a grammarian or a proofread because he says "each of whom who" and since neither you or others commenting noticed this or, at any rate, chose to comment on this, what can we deduce about y'all? Also, I'm sure you realize that those individuals have other things in common than their chabadity, like, say, a beating heart, so the letter writer ought to have added further restrictions on the domain of speculative commonness.