Lambdadelta is a character from the 2 Japanese anime/manga/VN series Higurashi No Naku Koro Ni (When The Cicadas Cry) and Umineko No Naku Koro Ni (When The Seagulls Cry).
There's this Umineko arc Memoirs of the ΛΔ. So in symbols 'Lambdadelta' is really ΛΔ instead of λδ, Λδ and λΔ? Well I guess the other option would be Λδ but probably not λδ or λΔ since I guess the lambda has to be capital.
Edit: Actually there's a spoilerous reason why the name 'Lambdadelta' is associated with the numbers 3 (or 30), 4 and 34. I read somewhere that if this is the case then we should keep both symbols capital. Any source possibly to confirm (or disprove) this?