Googology Wiki
Googology Wiki
Googology Wiki

Edit: I shouldn't put the number of symbols in the title, because if i find a mistake, i can't fix the title. So it's actually 387 symbols.

Edit 2: Emk found another mistake, but fixing it reduces the number of symbols to 346.

Edit 3: C7X changed the title to the correct one. Thank you C7X!

P-bot recently found a Rayo name for 65536 with only 442 symbols: https://googology.wikia.org/wiki/User_blog:P%E9%80%B2%E5%A4%A7%E5%A5%BD%E3%81%8Dbot/Rayo_name_of_65536

It can be reduced to 426 symbols by changing the IsOrdinal(x) to a shorter version, which was discovered independently by Emk and me. But P-bot used surjections, and a shorter result can be achieved with bijections. So instead of ●UniquelyWedges●To●(xi,xj,xk), i created ●Wedges●With●(xi,xj,xk), which has one addition: (¬∃xl((xl≠xj∧●Wedges●To●(xi,xl,xk))))

After Emk found a mistake, i had to remove the restriction that xj and xk must be different in ●Wedges●To●(xi,xj,xk), and i shortened ●Wedges●With●(xi,xj,xk) by joining the two parts that were almost identical, but with xj and xk swapped.

IsIncludedInV5(xi) is a modification of P-bot's ●IsIncludedInFourthPowerOf0(xi), which we get by adding "∃xo((xo∈xj∧" before the FormChain and adding "))" at the end. It's basically just making the chain 1 variable longer, which adds 10 symbols.

Is65536(xi) now says that xi is an ordinal and that there is an xk such that for everything in xi, xk wedges it with something in V5, and for everything in V5, xk wedges it with something in xi. In other words, xk is a bijection from xi to V5.

IsOrdinal(xi) (¬∃xj(∃xk(((xk∈xj∧xj∈xi)∧(¬(xk∈xi∧(¬∃xl((xl∈xk∧(¬xl∈xj))))))))))

3+4+4+3+3+3+3+3+3

+3+3+4+3+3+3+3 = 51

IsV5(xi) IsIncludedInV5(xi)∧●IncludesFifthPowerOf0(xi) 60+3+66 = 129
●Wedges●To●(xi,xj,xk) ∃xm((xj∈xm∧xk∈xm)∧xm∈xi) 4+3+3+3+3+3=19
●Wedges●With●(xi,xj,xk)

●Wedges●To●(xi,xj,xk)∧(¬∃xl(((xl≠xj∧xl≠xk)∧

∃xm(((¬((¬xj∈xm)∧(¬xk∈xm)))∧xl∈xm)∧xm∈xi))))

19+3+3+4+6+3+6+3+4

+3+3+3+3+3+3+3+3+3

+3 = 81

Is65536(xi)

IsOrdinal(xi)∧∃xj((IsV5(xj)∧∃xk((¬∃xl(((¬((¬xl∈xi)∧(¬xl∈xj)))∧

(¬∃xm((((¬(xl∈xi∧(¬xm∈xj)))∧(¬(xl∈xj∧(¬xm∈xi))))∧

●Wedges●With●(xk,xl,xm))))))))))

51+3+4+129+3+4+3+4

+3+3+3+3+3+3+3+3+4

+3+3+3+3+3+3+3+3+3

+3+3+3+81 = 346

Of course, we can change V5 to Vn+1 to get a formula for 2↑↑n, which has 266+20n symbols.