This report is discusses two new ideas. First, I discuss a re-orientation of existing logics and logical frameworks based on a presentation of logic as a state transition system. Second, utilizing this transition-based interpretation of logic, I present a safety proof for the SSOS specification of a simple sequential programming language, and discuss how that proof can be updated as the language is extended with parallel evaluation and exception handling.

]]>We present SEISMIC, a systems that enables WSDs and mics to operate on the same TV channel with zero audible mic interference. SEISMIC implements a MicProtector to measure the interference at the mic receiver and a signaling protocol to notify the WSD of impending interference. This allows the WSD to optimize its transmission (e.g. through subcarrier suppression) without impacting mics. We motivate and describe SEISMIC and present a detailed performance analysis that shows that SEISMIC can regain up to 95% of the spectrum in single mic scenarios, and up to 85% in many (10+) mic environments.

]]>In this paper, we present a focused sequent calculus for propositional intuitionistic logic and prove the focalization property relative to a standard presentation of propositional intuitionistic logic. Compared to existing approaches, the proof is quite concise, depending only on the internal soundness and completeness of the focused logic. In turn, both of these properties can be established (and mechanically verified) by structural induction in the style of Pfenning’s structural cut elimination without the need for any tedious and repetitious invertibility lemmas. The proof of cut admissibility for the focused system, which establishes internal soundness, is not particularly novel. The proof of identity expansion, which establishes internal completeness, is a major contribution of this work.

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