We will develop and implement new algorithms for constraint solving and apply them to construct two classes of tools: 1) bug finding and verification tools building on tools such as Java PathFinder and Jahob; 2) tools for deep semantic analysis of texts containing a mix of English, source code, and mathematical formulas. The starting point for our techniques are constraint solving algorithms developed in the rapidly expanding field of satisfiability modulo theories (SMT). We will use state-of-the art techniques to implement an SMT constraint solver in the Scala programming language running on JVM platforms. One of the distinguishing features of our constraint solver will be the ability to analyze rich constraints that include not only quantifiers, numerical domains and data structures, but also lambda expressions and recursive definitions. To be effective for program analysis, the constraint solver will have a native support for transition systems describing program semantics. This will enable it to tackle sources of exponential explosion in context-sensitive and path sensitive analyses such as symbolic execution. Such analyses can identify a wide range of bugs, many of which can cause crashes and security problems. In the area of text processing, we expect our constraint solver to enable efficient reasoning about rich semantic domains arising in computational semantics of natural language. This capability will make the solver a useful component of tools for creating semantically annotated text and post-processing search results in scientific and engineering domains. To evaluate this hypothesis, we will develop a tool for analyzing text whose subject is explanation of source code, programming language semantics, compilation, and program analysis.