Prolog and the z3 theorem prover are reliable ways to solve a logic puzzle — This post shows you two programmatic ways to solve logic puzzles, one using the Prolog programming language and the other using the z3 Theorem Prover. In an earlier post, written almost exactly one year ago today, I brute force solved a simple logic puzzle in Python. In it I also…

Why promote other brands? — Question: Why has Apple been spending millions on Google Ads for HBO Max? Answer: Because the revenue from ad conversions is greater than the cost of advertising. Welcome to Costs Matter, a series that asks different questions all of which have the same answer: to better manage costs. The costs…

All other children of wizards grew up in the wizarding world — Question: Why was Harry Potter raised by muggles? This constrasts with other wizard children. They all grew up in the wizarding world. Even if they weren’t in the wizarding world, they grew up aware of magic and sorcery. Answer: Because all of Harry Potter’s readers are muggles. J. K. …

Why the destruction? — Question: Amazon Warehouses often destroy unsold stock items. Sometimes millions of items are destroyed. Why? Answer: Because the cost of occupying an Amazon warehouse shelf exceeds the cost of keeping the item. Discarding the item is a cost savings. Welcome to Costs Matter, a series that asks different questions all…

Why only the females? — Question: why do shrimp farms blind their female shrimp? Answer: because captive sighted female shrimp do not develop ovaries. If you’re a shrimp hatchery with no reproducing shrimp you’ve just invested in a really expensive aquarium. Welcome to Costs Matter, a series that asks different questions all of which have…

Why the gender discrimination? What’s wrong with rooster meat? — Question: why are your rotisserie chickens hens not roosters? Answer: because roosters don’t reach adulthood. Welcome to Costs Matter, a series that asks different questions all of which have the same answer: to better manage costs. The costs are frequently economic though not always. The series focuses narrowly on the…

Why all the office perks? Why the free laundry and free massages? — Question: Why does Google give free lunches? Answer: By providing food within the office premises Google effectively encourages its employees to spend more time in the office. Employees spending more time in the office results in more productivity. The costs of providing food are less than productivity loss from employees leaving…

Why incur costs of managing a software team which does all this? — Question: Why does Ford automatically upgrade the software of its pickup trucks? What justifies the costs of software expertise needed to manage all this? Answer: Because the software upgrades lead to cost savings in their warranties. Welcome to Costs Matter, a series that asks different questions all of which have…

Why not use frustums? — Question: Why are barrels cylindrical? We saw last week that bucket-shaped-objects, technically called frustums, are better because they stack well within each other. So why use cylinders at all? Answer: Because for the same volume, right cylinders have a lower surface area than frustums. Welcome to Costs Matter, a series…