Various 31edo triads, 6th and 7th chords, named via ups and downs. Not meant to be exhaustive, but this list does demonstrate the basic rules for naming.

vm3 m3 ~3 M3 ^M3 v4 P4 ~4
triad Cvm Cm C~ C C^ Cv4 C4 C~4
~6 Cvm~6 Cm~6 C~6 C,~6 C^,~6 Cv4~6 C4~6 C~4~6
M6 Cvm,6 Cm6 C~,6 C6 C^,6 Cv4,6 C4,6 C~4,6
^M6 Cvm^6 Cm^6 C~^6 C,^6 C^6 Cv4^6 C4^6 C~4^6
vm7 Cvm7 Cmv7 C~v7 C,v7 C^v7 Cv4v7 C4v7 C~4v7
m7 Cvm,7 Cm7 C~,7 C7 C^,7 Cv4,7 C4,7 C~4,7
~7 Cvm~7 Cm~7 C~7 C,~7 C^,~7 Cv4~7 C4~7 C~4~7
M7 CvmM7 CmM7 C~M7 CM7 C^,M7 Cv4M7 C4M7 C~4M7
^M7 Cvm^M7 Cm^M7 C~^M7 C,^M7 C^M7 Cv4^M7 C4^M7 C~4^M7

A comma (the actual punctuation mark ",") is spoken as "add", thus C,v7 is "C add-down-seven". The only exception is when a comma separates two numbers, as in C4,7 which is "C four-seven". A comma is written, and "add" is spoken, whenever not doing so would cause confusion with another chord. C^,~6 is clear without a comma if limiting oneself to 31edo. However, 53-edo and other edos have an upmid 3rd and 7th, and C^~6 would be P1 ^~3 P5 ^~6. In addition, "upmid" is a general term for slightly sharp neutral. One could play an upmid chord on a 31edo guitar by bending the mid 3rd up slightly.

Note that 4:5:6:7 = C E G vBb is named C,v7 not Cv7 because Cv7 is an alternate name for C~v7.