Prav, Yav, Nav Symbolism

        Prav,         Yav,           Nav    Symbolism
        Guide,      Reality,     Void
cf.    Heaven   Earth         Underworld
These three terms play a seminal role in Russian Cosmology. Basic associations are outlined under the three terms proper. This results in their being integrated into the 8 spoked wheel of the year whereby Nav is 1 November (All Souls), Prav  is the Winter Solstice (21 December, cf. Yule, Christmas), and Yav is Candlemas (1 February). 
In a deeper approach, Prav, Jav and Nav are seen as 3 Roots (3 Корня)
3 Корня,    9 Миров,             24 Мирами
3 Roots      9 Peaces           24 Connections
                    9 Regularities
                    9 Emanations 
Миры Иггдрасиля
 Let us examine in more detail the quantitative characteristics of the paradigm:
3 “root” - the symbol of [trekhmiriya], [trekhtochiya], 3-dimensional nature, guide - reality - [Nav], triunity energy - information - measure.
9 “peaces” - 9 regularities, or 9 emanations of the manifestation of the universe.
24 connections between “the peaces” - correspond to twenty four to runes of the Scandinavian runic system “Of [futark]”. http://tvoyhram.ru/severnrelig/severnrelig26.html (via babelfish)
Through this symbolism the Yggdrasil World Tree becomes a starting point for the sequence 3, 9, 24 which in turn becomes one basis fro rune theory.
In a more complex approach each of the 3 domains of Prav, Jav, Nav generates a Great Trimain or Tryglav such that we have:
Great Trimain of Peace of Pravi
Great Trimain of Peace of Jav 
Great Trimain of Peace of Navi 
Each of these Great Trimains in turn generates 3 Gods who generate 3 gifts to mankind. In other words, Prav, Jav and Nav now play a central role in the birth of the gods and the creation story.
In other versions the trifold symbolism of Prav, Jav, Nav is expanded to a fourfold sysmbold which includes Slav.