What is the truncating vowel final stem that has an example of mama-s?
CREATE TABLE "nouns" (
  "consonant_final_stem" text,
  "example_k_ats_man" text,
  "vowel_final_stem_truncating" text,
  "example_mama_father" text,
  "vowel_final_stem_non_truncating" text,
  "example_sakartvelo_georgia" text
);
SELECT "vowel_final_stem_truncating" FROM "nouns" WHERE "example_mama_father"='mama-s';