Physicist reckons two-button calculator can do all elementary math
- Reference: 1776182790
- News link: https://www.theregister.co.uk/2026/04/14/two_button_calculator/
- Source link:
On this occasion, the honor goes to Andrzej Odrzywołek, a postdoctoral researcher at the Institute of Theoretical Physics, Jagiellonian University, Kraków.
In a recently updated, yet-to-be-peer-reviewed paper, Odrzywołek says he has, in essence, developed a two-button calculator that can compute the standard repertoire of a scientific calculator familiar to a high school math and science student. You might have to push the buttons a number of times, but the point is the underlying simplicity.
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A single two-input gate already suffices for all Boolean logic in digital hardware; Odrzywołek's claim is that continuous mathematics may have an analogous primitive. It can generate elementary functions from a single operator that would otherwise require multiple distinct operations. These include trigonometric functions such as sine, cosine, and tangent; algebraic functions; and arithmetic operations such as addition, subtraction, multiplication, and division. The two-input gate also produces constants including π, e (Euler's number, 2.71828...), and i (the square root of minus one).
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The proposed operator is eml(x, y) = exp(x) - ln(y). Eml is the exponential-minus-log function, exp is the exponential function, and ln is the natural logarithm (or the logarithm to the base e).
"A calculator with just two buttons, EML and the digit 1, can compute everything a full scientific calculator does. This is not a mere mathematical trick. Because one repeatable element suffices, mathematical expressions become uniform circuits, much like electronics built from identical transistors, opening new ways to encoding, evaluating, and discovering formulas across scientific computing," the paper says.
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It even has a diagram showing how the functions cascade from the proposed operator.
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Not everyone agrees, as [9]a lively discussion on Hacker News demonstrates. A couple of points first, though: the paper is about elementary functions in continuous mathematics, not discrete computation.
The author also points out there is no agreed list of elementary functions, and creates a list of the 36 most commonly used to get around the problem. The task, then, is to show whether every primitive on the list can be expressed as a finite composition of these two ingredients: eml(x, y) and a terminal symbol (e.g. the constant 1).
Odrzywołek also says that direct symbolic verification of the kind used in a formal proof is "intractable."
"The methods here are designed for speed and exhaustiveness, not for proof-level rigor. They use floating-point numerical evaluation and heuristic filtering," the paper's [10]Supplementary Information says. The numerical evaluation is the first of three steps, followed by verification and application.
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Whether the approach and the conclusion stand the test of time is unanswered. The author has yet to respond to our question about whether he is submitting the paper for peer review, but anyone with the requisite chops can kick the tires [12]here [PDF]. ®
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[10] https://arxiv.org/src/2603.21852v2/anc/SupplementaryInformation.pdf
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[12] https://arxiv.org/pdf/2603.21852
[13] https://whitepapers.theregister.com/
If you got 420 and you meant to get 69, just finger in plus -420. No need to reset.
I haven't read the paper, but you could add all the existing buttons on the calculator to a binary tree, and use the two buttons supplied to navigate through that to the function/input you want, and that could include a go back function.
That would get you to any value in the set of represented numbers but this is about continuous numbers, i.e. any two numbers that are not equal have an infinite number of possible numbers between them. You can't construct a tree with that property.
One button
I have an old car with a one button interface clock. Much like Morse code it uses timing to set. Therefore, I submit that a one button calculator would not only be possible but more efficient as well.
Re: One button
Just run through all the numbers until you get to the answer you wanted. When they do it with quantum it's called noise reduction.
Ideal for accountants: "What do you want the answer to be?"
Jagiellonian University, Kraków.
Sounds like perverse polish logic to me..
I can't read PDF on this device and I'm not a mathematician, but a comparison between his approach and lambda calculus might help me understand the former.
Brainfuck
One button for 0, the other for 1. As long as you know the length of the binary word, you're well away.
Cheating? So how about three presses to enter a character in Brainfuck. Also Turing complete, and processor independent to boot, but a whole 8 characters to choose from.
Also cheating? So how come this bright idea isn't?
This sounds very similar to the ultumate RISC CPU with only a single instruction of subtract and branch if negative. I was told about that over 20 years ago. Looking at Wikipedia it seems there are other options too.
https://en.wikipedia.org/wiki/One-instruction_set_computer#Subtract_and_branch_if_negative
An interesting thought experiment, but ultimately not useful.
Sounds very much like the Manchester Baby so it's as old as the stored-program computer itself.
Godel, Escher, Bach...
... contains some fairly good explanations of how few axioms and operations are needed to build a mathematical system, so I find this plausible.
Re: Godel, Escher, Bach...
Thanks for the reminder. It's a long time since I read it. I must look for my copy.
*Analog*
What you all seem to be ignoring is that the article specifically states that this is NOT digital computation.
(I recall seeing an old analog computer at my university, and that was when I was still a sprout. Even then it hadn't been used for years. Didn't seem very powerful.)
Apple did this before, for an entire keyboard
https://www.youtube.com/watch?v=9BnLbv6QYcA.
Favourite calculator...
I will surrender my HP11C when they take it from my cold dead hand.
Re: Favourite calculator...
Thank God Clive Sinclair didn't read this.
**New** Sinclair Scientific II
- 2 buttons
- 2 digits (One for mantissa, one for exponent)
Bonus Costdown: No need to screen-print the value of "e" on the case!
It won't be long before Micro$lop add a CoPrat button.
It sounds like the Pure Math equivalent of a Turing machine.
I'll trust him that it's a useful theoretical construct, but I wouldn't want either one on my desk.
I was thinking the analog equivalent of the NOR gate. Good enough to get Apollo 11 to the moon.
Can't help but remembering how genius my ZX Spectrum's keyboard was supposed to be, what with the preprogrammed BASIC commands on it, and how amazingly idiotic the one-button remote control on my RC Porsche 928 was. The one with the L/R and F/R joysticks was like 30% more expensive.
I am to this day proud I remember how the one-button remote worked. Mostly.
Do the two buttons include a reset button so you can go back to the beginning again when you go wrong with the long sequence of presses?