Mathematics » Logic & Set Theory An open sentence is a statement which contains a variable and which becomes a proposition when an element of the universal set is substituted for this variable. If the variable occurs more than once in the open sentence, the same element of the universal set must be substituted for it at each occurance.

Mathematics » Logic & Set Theory Two open sentences are said to be equivalent if and only if their truth sets are identical.

a file to which documents continue to be added

a reference model and standard (ISO 14721) that describes the components and processes necessary for a digital archive, including six distinct functional areas: ingest, archival storage, data management, administration, preservation planning, and access

Finance Credit account for which the only formal instrument of credit is the invoice.

Finance Purchases or sales of securities or other assets by the central bank.

Mining at or very near the surface, rather than from deep underground.