Category Archives: Taxi-and-other-stories

Which Street is More Important: Canner Street or Cold Spring Street

Is it possible that Cold Spring Street is as important as Canner Street?

I knew Canner Street from my earlier visits to Yale but Cold Spring Street was new to me. Naturally, I assumed that Canner Street was the important one among the two. One day, however, while walking home, I crossed Cold Spring Street and it seemed as wide and as impressive as Canner Street. Perhaps, I thought, Cold Street is as important as Canner Street, and just the fact that I did not hear about Cold Spring Street earlier made me think otherwise. This was an interesting novel thought, but soon enough I saw one major problem: I was actually walking in Canner Street, so it was not surprising that it looked as wide as Canner street. I quickly went to the real Cold Spring Street and then it also looked indeed as wide and as impressive as Canner Street. But I was fully aware that this impression might be biased by the previous one.

Some evidence that Canner Street is more important is that in the Whitney-Canner crossing there are traffic lights while in the Whitney-Cold-Spring crossing there is only a flashing yellow light. However, when you go on Orange Street the situation is reversed: The Orange/Canner crossing is a flashing yellow light and the Cold Spring Orange crossing has full-fledged traffic lights. You may say that prominent streets like Whitney and Orange themselves are more important than both Canner and Cold Spring streets. Be it as it may be, in this post we discuss only horizontal streets, and don’t touch at all on the importance of vertical streets. In fact, we compare only two streets, Canner Street and Cold Spring Street.

The following year my wife visited me at Yale and I told her about my inquiries regarding the relative importance of Cold Spring Street and Canner Street. My wife listened carefully, and even added one interesting piece of evidence that I did not consider before. My own street, Everit street (a small vertical street famous for hosting Yale’s president Rick Levin and the famous economist John G.), crossed Cold Spring Street but ended at Canner Street. My wife thought that this piece of evidence supported my feeling about the importance of Cold Spring street. I was not sure about it; to me it looks that Everit ending at Canner street rather than crossing  it,  gives Canner street some edge.

At some point I decided to test matters scientifically and I measured in steps the width of Canner Street. But I returned to Israel before making a similar measurenemt at Cold Spring Street and by now I forgot the outcomes.

Of course, we can say that Canner Street is the more important on its Whitney side and the less important on its Orange side. But this answer simply does not face the real problem. Perhaps an opinion poll can help.

At the end, after some years, I came to the conclusion that Canner Street is more important than Cold Spring Street because it extends beyond Whitney while Canner Street does not. (But please dont be influenced by me.)

Michal Linial: No Witches in Portugal

It gives me great pride to present:


Michal Linial:  March 2012

No witches in Portugal

Landing in LISBOA, Portugal last night. I need to get to my hotel in Cascais. The nice lady in the tourist information ordered a taxi and happily said: “Do not worry, our drivers speak excellent English.

Five minutes later my driver arrived, a huge person, nicely dressed with a fancy nice black car. “To Cascais, What is the price” I asked in a fluent English.  Well, it depends he replied…

My huge driver, was very fluent in English as promised… Then he starts… Three years ago I had a ski accident, at that time I was much heavier… I was wondering how such information might be relevant to our trip… My driver continues: “From the time of the accident my leg is not the same. This is why I bought this car with a “gear” instead of an automatic transmission, so I can practice my left leg. Most of time I can move it, but I still do not feel it when it is cold”… “Is it cold today?” I asked. No, today it is fine. Yesterday it was cold.

How long is it to Cascais? I was asking. My driver relied honestly: “it depends on the road”… Oh, I said… waiting for an explanation. It took a minute for him to explain: “You know, I always drive by my feelings. Sometime, I have a feeling that it is not good to take the freeway. Today I have this feeling. “OK, it is best that you listen to your feelings”, I relied quietly. He continues: “You know, there are no witches in Portugal, but it is better to listen to them”. Of course, I said.

You know he continue, my brother in law who was a driver in our taxi company had a bad feeling 4 months ago when he took the small road instead of the highway, and indeed he died. A truck crushed him. But the passenger, a British person that was in the car was not hurt. The passenger had his seat belt fasten, like you… Do you want me to show you where he died?, it is on the way to the hotel, he insisted. Sure I replied. If it is on the way, and you feels that we should not take the highway, let’s go on the other road…

We drove on a neglected road. It was not too cold… My huge driver mentioned me the spot where his brother in law died…  We are now 10 min from the hotel he updated me. But I missed the entrance. You know, he continued, once I drove with my mother, I missed the entrance to the road. Then, I knew that I should not get into this road. Do you mind that I will drop you here? it is no more than 200 meters to your hotel. I happily paid the 60 Euro, another tip for 10 Euro for the good witch that was with us.  

While I was walking with my luggage on the hill to the hotel, a taxi was stopping behind me. It was my big driver again… He said: I forgot to give you my card. Please call me when you want to go back to the airport. it will be only 30 Euro. We can take the highway. I am still in Portugal for another 2 days. I will call him if it will not be too cold.

The Möbius Undershirt

“Look at this brand new undershirt,” my wife said. “I am shaking it and shaking it but still I have this twist.  Can you see what to do?” 

I gave the undershirt a good shake. And another one. And one more. And then it struck me. It was a Möbius undershirt!

What a rare case in which mathematics can come to the rescue in domestic matters

“There is no way in the world this twist can be undone,” I said. “This is a mathematical fact! It is a Möbius undershirt!” My wife listened carefully to my firm statement.

I started to day-dream about the bright future of this rare Möbius undershirt: I will show her to my colleagues!, I will display her in public lectures, and even let some selected graduate students hold her. However, Continue reading

School Bus to Ramle


We had just come back to Israel from Palo Alto after spending a sabbatical year there and my child was starting school. I walked down with him to wait for the school bus. To my great surprise it was a yellow school bus just like in the US. The school bus driver checked the name and said “Yes, we are going to Ramle, get on”. “To Ramle?” I screamed “Why Ramle?”. Ramle is a small town 50 kilometers from Jerusalem. I walked up quickly and asked my wife “Ramle? why Ramle?” My wife listened carefully and replied: “Do you think it is a bad idea to send the child to Ramle?” “Of course!” I said. “It is too late now”, said my wife, “You shoule have thought about it while we were still in the US.” Continue reading

The Intermediate Value Theorem Applied to Football

My idea (in my teenage years) of how to become a professional basketball player was a bit desperate. To cover for my height and my athletic (dis)abilities, I would simply practice how to shoot perfectly from every corner of the court. I would not have to run or jump. My team could pass the ball to me at the right moment and I would shoot. (I was a little worried that once I mastered this ability they would change the rules of the game.)

But this idea did not work. As much as I practiced, I could not shoot perfectly from all corners of the court, and not even from the usual places. In fact, my shooting was below average (although not as much below average as my other basketball skills.)

Next came my idea how to become a professional football (soccer) player. This idea was based on mathematics, an area where I had some advantage over other ambitious sports people; more precisely, my idea was based on the intermediate value theorem. (We had a post about this theorem.)

The idea is this: If you put a football on your head and start running the ball will fall from behind. But if you put the ball on your forehead and start running the ball will fall in front of you. By the intermediate value theorem, there must be a point, in between, such that if you run with the ball at this point, the ball will not fall at all. In fact you can find such a point for every way you would like to run. And you can even learn to adjust it if you change your route!  The plan was now simple. At the right moment I would get the ball from my team, put it on the right point on my forehead  start running and slalom my way towards the goal. (I was a little worried that once I mastered this ability they would  change the rules of the game.) I practiced it for several weeks, Continue reading

Coffee, Cigarettes, and Aggression



Upgrade to hell

Getting an upgrade to business class on a flight to Amsterdam en route to NYC seemed splendid. But I soon discovered that I was upgraded to one of the two rows for business smokers.

The person on my left

The person to my left smoked Camel cigarettes. He had a pack of cigarettes on his table and he smoked a cigarette every 20 minutes. It was disturbing and I considered asking him not to smoke. But this was his right! He bought a business class ticket to the smoking section. I was just an upgrade, but even as a full-fledged businessman I would not have had the right to ask him not to smoke. 

An idea

I had another idea. When breakfast was served I had a cup of coffee on my tray, and the pack of Camel cigarettes was on my neighbors’s tray bordering mine. If I were to accidentally spill all my coffee on his pack, this may take the cigarettes out of action!

It was not an easy decision. Will it work? Is it morally justified?  Continue reading