NicoBey - Trephine

Books, Product Management, Maths & Physics, Environment

Random quotes 4

  • “Everybody at every level should have an equal voice in the outcome, based on the strength of his or her arguments.” / “If we have data, let’s look at the data. If all we have are opinions, let’s go with mine.” (James Barksdale)

  • “Les êtres passionnés par une seule idée me fascinent, car plus quelqu'un se limite, plus il s'approche en réalité de l'infini. Ces gens-là, qui semblent s'écarter du monde, bâtissent avec leur matériau particulier un univers en miniature.” (Stephan Zweig)

  • How can I show this (vs. tell) with the least number of graphs possible?

  • Trace the genealogy of your ideas

  • “Success can usually be measured by the number of uncomfortable conversations we are willing to have and the number of uncomfortable actions we are willing to take.” (Tim Ferriss)

  • “You never change things by fighting the existing reality. To change something, build a new model that makes the existing model obsolete.” (Buckminster Fuller)

  • “You never rise to the level of your vision. You fall to the level of your decision-making.” (Shreyas Doshi)

  • “Tout Homme qui dirige, qui fait quelque chose, a contre lui, ceux qui voudrait faire la même chose, ceux qui font précisément le contraire, et surtout la grande armée des gens, beaucoup plus sévères, qui ne font rien.” (Jules Claretie)

  • “Ultimately, what a product manager has to constantly fight is ambiguity” (Ken Morton)

  • There are 4 types of wealth: 1. financial wealth (money) | 2. social wealth (status) | 3. time wealth (freedom) | 4. physical wealth (health) be wary of a job that lure you in with 1 and 2 but robs you with 3 and 4.

  • “Run towards trouble. It will say a lot about your maturity and character.” (Shreyas Doshi)

  • “Pan metron ariston” (παν μέτρον άριστον) : “everything in moderation”. (Quote in ancient Greek coined by Kleovoulos o Lindios in the 6th century B.C.)

Other publication with random quotes , random quotes 2 , random quotes 3

Random quotes 3

  • “On ne construit pas un pont en comptant le nombre de personne qui traversent la rivière à la nage” (Brent Toderian)

  • “To see the world, things dangerous to come to, to see behind walls, to draw closer, to find each other and to feel. That is the purpose of life.” (James Thurber)

  • “C’est une intarissable source d’inspiration quand il s’agit d’aider quelqu’un à avancer, car je sais qu’il n’y a pas besoin de savoir où il compte aller, ni comment il va faire. Il suffit parfois d’être là, d’être attentif, d’être admiratif, de ne pas avoir peur de jeter une pincée d’absurde dans l’arène. Et d’oublier que l’on ne sait pas.” (Rémi Guyot)

  • “Beautiful things don't call for attention” (James Thurber)

  • “The reality is that we have zero years [to address Climate change] and we have to change all of our infrastructure.” (Saul Griffith)

  • “When you're the janitor, reasons matter. Somewhere between the janitor and the CEO, reasons stop mattering. That Rubicon is crossed when you become VP” (Steve Jobs)

  • “Le génie de cette voiture réside dans ses renoncements.” (Jean Savary en parlant de la Citroen Ami)

  • ” Un product manager doit non seulement prendre les bonnes décisions, mais aussi minimiser le coût nécessaire à la prise de ces décisions. En particulier, protéger le temps des autres équipes sollicitées pour informer ces décisions.” (Remi Guyot)

  • “the first kid is very hard to handle. the second makes you recognize how easy only one kid was. the third is raised by the first two, and the forth is raised by themselves.”

  • “une solution qui vous démolit vaut mieux que n’importe quelle incertitude” (Boris Vian)

  • “Those who make peaceful revolution impossible, make violent revolution inevitable” (John f. Kennedy)

Other publication with random quotes , random quotes 2

Beauty in formulas

It's everywhere.

Formula for 3, by Ramanujan : Rmanujan's formula for 3 Euler's formula : Euler formula

The logistic map : logistic map

The Classical wave equation : Classical wave equation

Other publication on mathematics Riemann hypothesis – a tentative at making it accessible

Chronique littéraire 13

Dan Ariely – Predictably Irrational

Another book about behavioural economics & psychology... Although there are some similarities between Thinking, Fast & Slow, in Predictably Irrational, Dan has kept the topics brief and discussions to the point with very few experiments/studies. The interest is hence better sustained, and the read easier. The premise of the book is that human beings make consistently irrational decisions. The author tries to uncover the root causes, and effects of these behaviors. For instance, he shows the huge difference there is between “almost free” and “free”; he explores the 2 norms that we live by all the times : social vs. market; he explains how and why ownership distorts the perception of value... A must-read for product managers, marketers, and everyone that can benefit from knowing more about sociology !

  • “humans rarely choose things in absolute terms. We don't have an internal value meter that tells how much things are worth. Rather, we focus on the relative advantage of one thing over another, and estimate value accordingly”

  • “Most people don't know what they want until they see in context”

  • “we find it easy to spend $3,000 to upgrade to leather seats when we buy a new $25,000 car, but difficult to spend the same amount on a new leather sofa”

  • “The more we have, the more we want. And the only cure is to break the cycle of relativity”

  • “Herding : When we assume something is good or bad on the basis of other people's previous behavior, and our own action follow suit. But there is also another kind of herding, one that we call self-herding. This happens when we believe something is good (or bad) on the basis of our own previous behavior.”

  • “Why do we have an irrational urge to jump for a FREE! item, even when it's not what we really want ? I believe the answer is this. Most transactions have an upside and a downside, but when something is FREE! we forget the downside. FREE! gives us such an emotional charge that we perceive what is being offered as immensely more valuable that it really is. Why ? I think it's because humans are intrinsically afraid of loss”

  • “Money is very often the most expensive way to motivate people”

  • “Life with fewer market norms and more social norms would be more satisfying, creative, and fun”

  • “When prices are zero and social norms are part of the equation, people look at the world as a communal good. [...] Not mentioning prices ushers in social norms, and with those social norms, we start caring more about others”

  • “we are in love with what we already have”

  • “Our aversion to loss is a strong emotion, [...] one that sometimes causes us to make bad decisions. [...] we often refuse to sell some of our cherished clutter, and if somebody offers to buy it, we attach an exorbitant price tag to it”

  • “In 210 BC, a chinese commander named Xiang Yu led his troops across the Yangtze river to attack the armi of the Qin dynasty. Passing on the banks of the river for the night, his troops awakened in the morning to find, to their horror, that their ships were burning. They hurried to their feet to fight off the attackers, but soon discovered that it was Xiang Yu himself who had set their ships on fire, and that he had also ordered all the cooking pots crushed. Xiang Yu explained to his troops that without the pots and the ships, they had no other choice but fight their way to victory or perish. That did not earn Xiang Yu a place on the Chinese army's list of favorite commanders, but it did have a tremendous focusing effect on his troops: grabbing their lances and bows, they charged ferociously against the enemy and won nine consecutive battles, completely obliterating the main-force units of the Win dynasty”

  • “What we need is to consciously start closing some doors.”

  • “Why are we so frequently dishonest ? This is my take. We care about honesty and we want to be honest. The problem is that our honesty monitor is active only when we contemplate big transgresssions, like grabbing an entire box of pens from the conference hall. For little transgressions, like taking a single pen or two pens, we don't even consider how these actions would reflect on our honesty and so our superego stays asleep.”

  • “Individuals who had mastered [...] knowledge, it was said, not only had a monopoly of practice of that knowledge, but had an obligation to user their power wisely and honestly. The oath – spoken and often written – was a reminder to practitionners to regulate their own behavior. “


I published a 2-parts story on Focus :

  1. Focus : the Beauty of Theory This part explains why Focus is so important, and why, in theory it shouldn't be too difficult. Quote : “Managing too many topics in parallel is biologically unnatural and counterproductive.”

  2. Focus : the Beast of Practice This part explores why it's so difficult to achieve focus in reality, and suggests concrete methods to get better at it. Quote : “Today, everything is presented as an opportunity, and distractions are everywhere.”

Happy to get your feedback on it :)

Riemann hypothesis – a tentative at making it accessible

This article aims at dumbing down what the Riemann hypothesis is and its link to primes number for anyone – with or without mathematical background

PART 1 - On prime numbers, what they are, why they are key and what we miss about them

Primes : prime numbers are numbers that are divisible only by 1 and themselves. You cannot decompose them through a multiplication with any other number. Example : 24 is 6x4 or 2x12 or 1x24 : it's not prime. But 17 is... well, only 17x1 : it's prime

What is key is that you can decompose ANY number as a multiplication of prime numbers – and reversely you can build ANY number with primes. Example : 232 is 2 x 2 x 2 x 29 when decomposed in prime factors

In other words, primes are the building blocks of numbers.

Together, they are a bit like the periodic table in chemistry, or the design system of numbers : they represent the minimum and complete set you need to build every number.

The issue we have is that we don't know where they are. If I give you a prime number like 23 367 457, we do not have a formula giving you the prime that follows it. We are forced to test manually, one by one, the ones that follow. This means that we don't know the periodic table of numbers !

Of course this has been bugging mathematicians for centuries. Until B. Riemann, a German mathematician from the XIXth c., wrote a very short paper (9 pages!) that revolutionized our understanding of it.

He created a formula that is called a “prime counting function”, which basically increases by 1 every time you cross a prime number. It looks like the graph below – a “staircase”.


If you have a formula that describes this graph at any point – you actually know where all primes are ! But the problem is not really solved today...

Why ? See part 2 below !

PART 2 - On Riemann hypothesis : Million dollar baby !

The formula that Riemann built, starts from a simple approximation of this function, looking like an almost-straight line. It's the Li(x) that you see below.


Then, he adds up infinitely many small corrections to it. When added, these corrections change the originally simili-straight line to approach exactly, little by little, the “staircase” (below : blue=staircase, red=approximation with a few corrections on the left, and more corrections on the right. You see how the function approaches the staircase)

Prime counting fc approx 1
Prime counting fc approx 2

These little corrections are based on another function (the Riemann zeta function) that Riemann devised as well. More precisely, the corrections are based on the values that make this function equal to 0. Such values are called... zeros.
Example : a zero of the function x²-4 is 2, because 2²-2=0

And we don't know where primes are, because we don't really know where these zeros are. Ok, I lied a bit here : we have a pretty good idea of where they are, but it has never been proven.

The Riemman hypothesis describes where all these zeros are.

This hypothesis is so important to math, that the Clay institute has put a price of 1 million $ for everyone who will prove or disprove this hypothesis. It is one of seven so-called “Millennium Prize Problems” with such a prize attached.

Of course, it's far from being easy. It's so complicated actually, that the person verifying this hypothesis will stand on equal ground with Einstein, Pythagoras or Newton.

To conclude this thread, 2 fun facts about all this : 1. Riemann was pretty sure his hypothesis was true, but said casually in his paper “I have, though, after some fleeting futile attempts, provisionally put aside the search”. He died unfortunately at 39 and never resumed it... 2. a LOT of other theorems and conjectures have been proven by assuming Riemann's hypothesis ... This means that proving it (resp. disproving it) would validate (resp. put to the bin) a huge chunk of recent analytical mathematics, at once !

Resources : – The Riemann hypothesis, explained, by Jørgen Veisdal on Medium (requires mathematical knowledge though) – Riemann hypothesis, by Numberphile on Youtube


Se faire un doux chez soi, même au bout de la terre, Même tout près des toits fumeux, dans la cité: Là, vivant en soi-même et du monde abrité, Des loisirs studieux goûter le charme austère;

Cheminer vaillamment, à deux ou solitaire, Dans la clarté, dans l'idéal, dans la beauté. Au sommet de sa vie asseoir la vérité; Sans trouble, de la mort accepter le mystère;

Tendre au juste avenir une oeuvre au pur essor; Adoucir aux vaincus la cruauté du sort, Aimer d'un grand amour les choses émouvantes:

La Poésie, l'Art les monts dans leur splendeur, La mer, la paix du soir aux campagnes dormantes, C'est la sagesse... et c'est peut-être le Bonheur

Amic Duthuzo

Chronique littéraire 12.2

This is the follow-up article of chronique littéraire 12.1 on Thinking, Fast and Slow by Daniel Kahneman.

–“If you visit a courtroom you will observe that lawyers apply two styles of criticism: to demolish a case they raise doubts about the strongest arguments that favor it; to discredit a witness, they focus on the weakest part of the testimony.”

-“Subjects' unwillingness to deduce the particular from the general is matched only by their willingness to infer the general from the particular”

–“Confidence is a feeling, which reflects the coherence of the information and the cognitive ease of processing it.”

-“Success = talent + luck / Great success = a little more talent + a lot of luck”

–“The idea that large historical events are determined by luck is profoundly shocking, although it is demonstrably true.”

-“The statement 'Hitler loved dogs and little children” is shocking no matter how many times you hear it, because any trace of kindness in someone so evil violates the expectations set up by the Halo effect”

–“Those who know more, forecast very slightly better than those who know less. But hose with the most knowledge are often less reliable. The reason is that the person who acquires more knowledge develops an enhanced illusion of her skill and becomes unrealistically confident”

–“Marital stability is well predicted by the formula : [frequency of lovemaking] – [frequency of quarrels]. You don't want your result to be a negative number”

–“The two basic conditions to acquire a skill are an environment that is sufficiently regular to be predictable, and an opportunity to learn those regularities through prolonged practice. When both these conditions are satisfied, intuitions are likely to be skilled.”

–“Overly optimistic forecasts of the outcome of projects are found everywhere”

–“a CFO who informs his/her colleagues that 'there is a good chance that the S&P returns will be between -10% and +30%' can expect to be laughed out of the room. The wide confidence interval is a confession of ignorance, which is not socially acceptable for someone who is paid to be knowledgeable in financial matters.[...] confidence is valued over uncertainty. An unbiased perception of uncertainty is a cornerstone of rationality. But it is not what people and organizations want”

–“Subjective confidence is determined by the coherence of the story one has constructed, not by the quality and amount of the information that supports it”

–“A risk-averse decision-maker will choose a sure thing that is less than expected value, in effect paying a premium to avoid the uncertainty.”

Chronique littéraire 12.1

Daniel Kahneman – Thinking, fast & slow

The book is rather a challenging read but I highly recommended it if you're interested in why human beings behave the way they behave. A reference in the field of behavioural economics & psychology, it's the kind of book that will make you say : 'oh, so that's why we're so dumb'. A LOT.

As a Product Manager, it helped me several times understand or anticipate how users acted or were going to act. I invite you to check further concepts if needed : they are all very well documented online. As the book is very dense, I split this chronique littéraire in 2 parts.

  • “The common admonition to 'act calm and kind regardless of how you feel' is a very good advice: you are likely to be rewarded by actually feeling calm and kind.”

  • “Money-primed people become more independent than they would be without the associative trigger. They persevered almost twice as long in trying to solve a very difficult problem before they asked the experimenter for help […]. Money-primed people are also more selfish.”

  • “If the answer was familiar, I assumed that it was probably true. […] the impression of familiarity is produced by System 1, and System 2 relies on that impression for a true/false judgement a reliable way to make people believe in falsehoods is frequent repetition, because familiarity is not easily distinguished from truth.”

  • “If you care about being thought credible and intelligent, do not use complex language where simpler language will do. My Princeton colleague Danny Oppenheimer refuted a myth prevalent among undergraduates about the vocabulary that professors find the most impressive. In an article titled “consequences of erudite vernacular utilized irrespective of necessity : problems with using long words needlessly”, he showed that couching familiar ideas in pretentious language is taken as a sign poor intelligence and low credibility. In addition to making your message simple, try to make it memorable. Put your ideas in verse if you can; they will be more likely to be taken as truth.”

  • “System 2 is lazy and mental effort is aversive.”

  • “90% of students who took the test in normal font at least one mistake in the test, but the proportion dropped to 35% when the font was barely legible. You read this correctly. Performance was better with bad font. Cognitive strain, whatever its source, mobilizes system 2, which is more likely to reject the intuitive answer suggested by system 1”

  • “I'm in a very good mood today, and my system 2 is weaker than usual. I should be extra careful.”

  • “The main function of system 1 is to maintain and update a model of your personal world, which represents what is normal in it.”

  • “Jumping to conclusions is efficient if the conclusions are likely to be correct and the costs of an occasional mistake acceptable, and if the jump saves much time and effort. Jumping to conclusions is risky when the situation is unfamiliar, the stakes are high, and there is no time to collect more information.”

  • “[in a test with a legal case] Participants who heard only one side could easily have generated the argument for the other side. Nevertheless, the presentation of one-sided evidence had a prnounced effect on judgements. Furthermore, participants who one-sided evidence were more confident of their judgments thatn those who saw both sides; […] It is the consistency of the the information that pmatters for a good story, not its completeness. Indeed you will often find that knowing little makes it easier to fit everything you know into a coherent pattern.”

  • “System 1 is highly adept in one form of thinking – it automatically and effortlessly identifies causal connections between events, sometimes even when the connection is spurious.”

  • “Extreme outcomes are most likely to be found in sparsely populated countries. […] the results of large samples deserve more trust than smaller samples. Large samples are more precise than small samples = Small samples yield extreme results more often than large samples do

  • “Because of the coincidence of two planes crashing last month, she now prefers to take the train. That's silly. The risk hasn't really change, it is an availability bias”

  • “Protective actions […] are usually designed to be adequate to the worst disaster actually experienced [e.g.] assuming that floods will not rise higher than the existing high-water-mark. Images of a worse disaster do not come easily to mind.”

  • “You surely understand in principle that worthless information should not be treated differently from a complete lack of information, but WYSIATI makes it very difficult to apply that principle. Unless you decide immediately to reject evidence, your system 1 will automatically process the information available as if it were true.”

  • “The idea of conjuncture fallacy, which people commit when they judge a conjunction of two events (here being a bank teller and a feminist) to be more probable than one of the event (bank teller) in a direct comparison [...] When you specify a possible event in greater detail you can only lower its probability”

  • “The laziness of System 2 is part of the story. If their next vacation depended on it, and if they had been given indefinite time and told to follow logic and not answer until they were sure of their answer, I believe that most of our subjects would have avoided the conjunction fallacy.”

Chronique littéraire 11 (Jackson)

Phil Jackson – Sacred Hoops (Spiritual lessons of a hardwood warrior)

In this book co-written by Phil Jackson (NCAA & NBA player, then coach in the NBA – in particular coach of the early 90’s Chicago Bulls that includes Michael Jordan) and Hugh Delehanty (senior editor, expert in sports and psychology), we almost follow the biographical path of Phil Jackson, and how he went from a growing up in a very Pentecostal family to a journey of discovery of Zen and Native American philosophy (esp. Lakota Sioux’ one), and how this intertwined and enriched with his basketball and personal lives.

Based on concrete situational examples he went through, Phil Jackson shows the challenges he faced in basketball as a player and coach, and in the relationships he built (with the general manager of the club, with other coaches, with players individually, with players as a conductor of a team…)

Very accessible, this book does not require any particular knowledge of basketball (even if having some will help). And everyone can get something out of it.

  • “Now he was an older, wiser player who understood that it wasn’t brilliant individual performances that made great teams, but the energy that’s unleashed when players put their egos aside and work toward a common goal”

  • “A great basketball team will throw the ball to everyone. If a guy drops it or bobbles it out of bounds, the next time they’ll throw it to him again. And because of their confidence in him, he will have confidence”

  • “There’s an old Zen story that illustrates this point. Two monks were traveling together in a heavy downpour when they came upon a beautiful woman in a silk kimono who was having trouble crossing a muddy intersection. ‘Come on’ said the first monk to the woman, and he carried her in his arms to a dry spot. The second monk didn’t say anything until much later. Then he couldn’t contain himself anymore : 'we monks don’t go near females’, he said. 'Why did you do that?’ – 'I left the woman back there’, the first monk replied, 'are you still carrying her?’

  • “According to Suzuki, concentration comes not from trying hard to focus on something, but from keeping your mind open and directing it at nothing”

  • “The wise leader is of service : receptive, yielding, following.”

  • “In Zen it is said that the gap between accepting things the way they are and wishing things them to be otherwise is “the tenth of an inch between heaven and hell”

  • “Albert Einstein once described his rule of work : “one : out of clutter, find simplicity. Two : from discord, find harmony. Three: in the middle of difficulty lies opportunity”

  • “The ego-driven culture of basketball, and society in general, militates against selfless actions, even for members of a team whose success as individuals is tied directly to the group performance”

  • “Inevitably, paradoxically, the acceptance of boundaries and limits is the gateway to freedom.”

  • “To the Lakota Sioux, everything was sacred, even the enemy, because of their belief in the interconnectedness of all life.”

  • “In the beginner’s mind there are many possibilities, in the expert’s mind there are a few”

  • “I believe that if I can take twenty of thirty minutes before each game and visualize what’s going to happen, I’ll be able to react to it without thinking, because I’ll already have seen it in my mind”

  • “There is no need to overpower when you can outsmart”

  • “See beyond what is seen. Never forget that a wheel is made not only of spokes, but also the space between the spokes. Sturdy spokes poorly placed make a weak wheel. Whether their full potential is realized depends on the harmony between. The essence of wheel-making lies in the craftsman’s ability to conceive and create the space that holds and balances the spokes within the wheel”

  • “Impermanence is a fundamental fact of life”

  • “I used to believe that the day I could accept defeat was the day I would have to give up my job. But losing is as integral a part of the dance as winning. Buddhism teaches us that by accepting death, you discover life”

  • “Our whole social structure is built around rewarding winners, at the perilous expense of forsaking community and compassion”

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