1. A KEYNESIAN APPROACH TO FISCAL POLICY FOR FULL EMPLOYMENT AND CONTINUOUS TIME DEBT DYNAMICS. Authors: YASUHITO TANAKA.2. INVOLUNTARY UNEMPLOYMENT IN A NEOCLASSICAL MODEL. Authors: YASUHITO TANAKA.3. MICROECONOMIC FOUNDATION OF THE PHILLIPS CURVE. Authors: YASUHITO TANAKA.4. INVOLUNTARY UNEMPLOYMENT UNDER ONGOING NOMINAL WAGE RATE DECLINE IN OVERLAPPING GENERATIONS MODEL. Authors: YASUHITO TANAKA.