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Cake day: December 21st, 2023

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  • India: what India does wayyy better than others is digital payments. we have what is called UPI this is a open payments interface made by government (rbi) but their APIs can be used by any bank’s and any verified third party apps, and all you need to use UPI is just a bank account that’s it, and with this we can send money to any bank account through any other bank account with just phone number or QR code, the reciver and sender don’t even have to use same app because the backend is same for all, i just have to search for their number and send money, or i just have to scan QR code and send money, and it happens instantly with no minimum limit, this is so widely used that pretty much any shopkeeper keeps a UPI qr code even the ones in smallest and remote villages. infact i dony think I used single rupee in cash since like last 3 years, i don’t carry cash anywhere either, this is integrated with popular apps too like uber online food ordering apps , Netflix and basically any app that needs payment. upi is pretty much only reason why India has the most digital transaction in world even more than China and it’s not even close.

    also public digital infrastructure, pretty much anything government related is done digitally, like our id cards, driving licence, income certificate, and even high school and degree certificate is digitised, infact even our college credits is digitised, like my college credits will be automatically added so it will be seamless to change college in between my degree, and ofc all this is verified cryptographically with an app, so it’s not just one pdf which can be forged or something. and recently a law was passed which made the cryptographically verified digital documents legally same thing as physical one’s, so now if you have a phone with the app installed ( government made app that store’s and verifies documents) and if you have all your documents in that app you are good to go anywhere. this is more than just concinence of not having to carry physical documents because now we can make bank accounts completely online because verification can be done through their APIs and cryptographically. and yeah it was super useful in covid times because we could do appointment for vaccination online in the app and we could get covid certificate digitally.




  • It’s called countable and uncountable infinity. the idea here is that there are uncountably many numbers between 1 and 2, while there are only countably infinite natural numbers. it actually makes sense when you think about it. let’s assume for a moment that the numbers between 1 and 2 are the same “size” of infinity as the natural numbers. If that were true, you’d be able to map every number between 1 and 2 to a natural number. but here’s the thing, say you map some number “a” to 22 and another number “b” to 23. Now take the average of these two numbers, (a + b)/2 = c the number “c” is still between 1 and 2, but it hasn’t been mapped to any natural number. this means that there are more numbers between 1 and 2 than there are natural numbers proving that the infinity of real numbers is a different, larger kind of infinity than the infinity of the natural numbers