“allowable expenditure”  means expenditure which, subject to the provisions of this Part, is allowable as mentioned in subsection (4) of the principal section;

“the new asset”  means the asset referred to in subsection (1) of the principal section which was acquired or brought into existence, or the value of which was enhanced, as a result of the incurring of the allowable expenditure;

“the principal section”  means section 3 of this Act;