1 If the stem of the yo form is exactly the same as the stem of the infinitive, the verb is regular; use this stem and attach the appropriate endings [the endings for the subjunctive are for the most part the opposite conjugation endings of the present indicative].
Inc (Incorporated) and Corp (Corporation or Corporated) are both shorthands for a certain business entity - a Corporation. An LLC is also an abbreviation for a business entity - a Limited Liability Company.
Inc. is the abbreviation for incorporated. A corporation is a separate legal entity from the person or people forming it. Directors and officers purchase shares in the business and have responsibility for its operation.