EXCEPTIONS OF वृद्धि-सन्धि - 2

In the following cases, instead of the substitution of वृद्धि vowels in place of गुण vowels occurring after अ/आ, गुण vowels are only substituted.

• When अ/आ occurs before एव showing an indefinite sense in a sentence.
  E.g. क्व + एव असि? क्वेव असि? "Where are you now?" (The place is not definitely known)
• The अ/आ occurring before ओम् is dropped.
  E.g. ब्रह्मा + ओम् = ब्रह्मोम् (not ब्रह्मौम्) ।      
• The अ/आ occurring before आ(उपसर्ग) is dropped.
  E.g. ब्रह्मा + एहि = ब्रह्मा + आ + इहि = ब्रह्मेहि ।
• In a समास, when a पद ending in अ/आ occurs before ओतु - a cat , or ओष्ठ - the lower lip, the वृद्धि substitution is optional.
  E.g. स्थूल + ओतुः = स्थूलोतुः or स्थूलौतुः ; and बिम्ब + ओष्ठी = बिम्बोष्ठी or बिम्बौष्ठी ।