Given the following groups of corresponding phonemes or phoneme sequences in Sanskrit, Greek, and Germanic: (1) v/ϝ/w, r/ρ/r, n/v/n, (2) u/v/u, r/ρa~aρ/ur, a/α/un, and (3) uv/v(ϝ)/(uw), ir(ur)/αρ/ur, an/av/un: the segments of sound lying behind group 1 were once in complementary distribution both with those behind group 2 and with those behind group 3. For the older stages of Indo-European, therefore, one needs to reconstruct only three entities: w, r, n (and likewise y, l, m for other sets not listed here), each with three positional variants of varying syllabicity. The argument has been most fully presented by Franklin Edgerton. In connection with that argument there has been some discussion whether the syllabic element in group 3 above should or should not be written ъ. Assuming for the moment that ъ has to be reconstructed in the neighborhood of stops to account for quattuor, πíσυρ∈s, and the like, the dilemma resembles that posed by the [k] of length in the description of some types of English : if we are impressed by its similarity to other [k]-like segments in environments where it is not automatically present, we say that there are some environments in which [k] is automatic but is phonemically /k/ nevertheless; but if we are more impressed by the automatic nature of its presence in length, we seize upon any phonetic detail that may distinguish this [k] from other [k]-like sounds elsewhere and see in the sequence [
] merely the allophone of /
/ before /θ/.2a If ъ is not recognized in quattuor, the problem hardly arises in the case of the nasals and liquids. For (i)y and (u)w it still exists, in a somewhat different form; but this question is here left out of account.