Fibonacci Day is November 23rd, and celebrates the work of medieval mathematician Leonardo of Pisa. We have no solid dates on Leonardo, but 11-23 was chosen as those are the first numbers in the sequence. In honour of the day, Science Magazine published an article on an American mathematician who utilized the Fibonacci series to solve German mathematician David Hilbert’s 10th problem of his original list of twenty-three.

Her name was Julia Robinson.

## Who is Fibonacci and why do we care?

Leonardo Fibonacci, slang for Filius Bonacci, son of Bonacci, was a medieval Italian mathematician who wrote Liber abaci “Book of the Abacus” in 1202. He was the first European work on Indian and Arabian mathematics and discovered an intrinsic and self-evident algorithm that appears throughout nature.

This is called a “Fibonacci sequence” in his honour and is simple enough: the sum of the two preceding numbers make the next in the series. Thus 1, 1 = 2, 1+2 =3, 3+2=5, 4+5=8 and so on down the line. It is used everywhere including in technical analysis for analyzing stock market charts where lines on a price volume chart are drawn using Fibonacci Retracements, Fibonacci Time Series, and Fibonacci Arcs.

But the most common appearance of a Fibonacci series is in nature, as in the agave plants leaves below. It is a recursive number sequence because to go forward you must go back, much like back stitch in blackwork embroidery.

## Fibonacci numbers in botany

Fibonacci numbers are also exemplified by the botanical phenomenon known as phyllotaxis where the whorls on a pinecone , pineapple, or petals on a sunflower follow a sequence of Fibonacci numbers or the series of fractions

## David Hilbert poses a problem; Julia responds

Julia Robinson wanted to know the answer to Hilbert’s 10th problem. She worked on it, and found no solution. Just after her 50th birthday, in 1969, twenty two year old Soviet mathematician Yuri Matiyasevich announced that he had solved the problem and acknowledged her paper on how to algorithmically compute functions (also called the recursive functions) as key.

Her paper uses not only the Fibonacci sequence but the Turing wheel for support.

Hilbert’s 10th Problem Find an algorithm to determine whether a given polynomial Diophantine equation with integer coefficients has an integer solution. | Resolved. Result: Impossible; Matiyasevich’s theorem implies that there is no such algorithm. |

### Julia’s Genethetical Chart.

Julia was born on December 8 1919 in Saint Louis, Missouri to Ralph Bowers Bowman and Helen Bowman who died when Julia was two. Her father remarried and moved the family out to California where Julia got both rheumatic and scarlet fever. In 1936, Robinson entered San Diego State University at the age but transferred to UCal Berkeley in 1939 where she met Raphael M. Robinson, her mentor and later husband. Her specialty was game theory and she was the first female mathematician to be elected to the National Academy of Sciences.

Her Ascendant is 28 Scorpio, [HS] a book about memory techniques or the ability to bring into being a state of accord a system. Her Moon is incredibly fast at 15.07 and then while her Mercury is just 4 degrees away, it is in another sign at 03 Sagittarius 21, making it unfettered. Thankfully her Mercury is also retrograde giving Mrs. Robinson the ability to jump forward in her thought process and visualize what she was looking for, and then be able to trace that process back and write it in mathematical notation. We have not run into this configuration previously.

## Footnotes:

- I saw this article in Science News and was captivated, so I did her chart. That’s usually how it works.
- Julia’s sister, Constance Reid, wrote a biography on both Julia and German mathematician David Hilbert.

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