### Why I still haven’t found a life partner

Yesterday I downloaded an audio book from Audible.com – which is called The Mathematics of Love, written by Hannah Fry who seems to be a pretty charming mathematician, who also from time to time making some YouTube Numberphile videos such as this one.

Never mind… The point is in her book she mentioned a method I used previously on a beer conversation with my lovely colleagues, a method can help you calculate how many potential life partners are out there waiting for you to be find. (I guess every single man or woman with a little of brain function would have probably thought about the same question at least once when he or she was half way intoxicated and there happened to be a young couple across the bar kissing as if they were the main actors of the show that evening…)

Anyway, the method is, actually very simple, just using the number of total potential partners, multiply by a few factors each from a certain perspective can help you estimate how many percentage of them are actually can be your life partner. It said to be the same way scientists try estimate the number of highly evolved civilizations that might exist in our galaxy (Drake equation), mentioned by Hannah in her book when referring a paper called Why I don’t have a girlfriend – by Peter Backus.

$G = N \cdot f_W \cdot f_A \cdot f_S \cdot f_U \cdot f_{B1} \cdot f_{B2} \cdot f_{P1} \cdot f_{P2} \cdot f_f$

I remember I did the calculation, once, for the fun of it, together with my colleagues, and the result was quite shocking. So I am going to do it here again:

Suppose I live in Denmark, and the whole population is around N=6,000,000, and we assume:

• $f_W$ = the fraction of people in DK who are women = 0.5;
• $f_A$ = the fraction of the women in DK who are age-appropriate = 10 years out of 70 years (suppose the age is evenly distributed) = 1/7;
• $f_S$ = the fraction of the women with the right age are single = 0.5;
• $f_U$ = the fraction of the women who have a university education = 0.26 (no offense but I have the same reason with the guy mentioned in the paper Why I don’t have a girlfriend;
• $f_{B1}$ = the fraction of the women with the right age with the right education who I find physically attractive = 2 out of 10 = 0.2;
• $f_{B2}$ = the fraction of the women with the right age with the right education who find I physically attractive = 2 out of 10 = 0.2; (Let’s say I am average looking, if you don’t agree, comments below and I will reduce this value);
• $f_{P1}$ = the fraction of the women with the right age with the right education who we both find attractive and who think my personality is acceptable also enjoy being with me, or you may call it have a word to say between = 0.5;
• $f_{P2}$ = chance that I enjoy being with her, same above = 0.5;
• $f_f$ = sadly because I am a foreigner who don’t speak Danish yet so maybe half of the women in the end decided not to date me = 0.5.

Thus, we can easily calculation G, which is the possible number of ladies in Denmark could become a life partner of mine:

$G = 6e10^6 \cdot 0.5 \cdot {1 \over 7} \cdot 0.5 \cdot 0.26 \cdot 0.2 \cdot 0.2 \cdot 0.5 \cdot 0.5 \cdot 0.5 = 279$

My goodness, only 279 women are out there in DK could be my life partner, based on a positive estimation.

However since I live in a town called Odense, suppose if I don’t go out of the town and just try to meet some local people, with the population of 190,000 in Odense, the number G becomes 8.8. It seems not that bad, but if you look at the numbers again, you will see, statistically, out of every thousand girls at the right age, there’s only a half girl could potentially become my life partner. What a lonely planet ?!

The next question to think about is, how to identify those 279 ladies in Denmark, I mean at least efficiently using my spare time. At the moment, I have no idea 🙂