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For example, little knowledge of the theorem prover is required for syntax and type checking, schema expansion, and precondition calculation. Even with domain checking, many of the proof obligations are easily proven. In more difficult cases, generating the proof obligation is often a substantial aid in determining whether a specification is meaningful. Our extensions add prover commands, a paragraph that expresses a theorem, and a means for attaching labels to predicates in an axiomatic or generic box. All rights reserved.