We present Cobra, a modern proof presentation framework, leveraging
cutting-edge presentation technology together with a state of the art
interactive theorem prover to present formalized mathematics as active
documents. Cobra provides both an easy way to present proofs and a novel
approach to auditorium interaction. The presentation is checked live by the
theorem prover, and moreover allows for live changes both by the presenter and
the audience.Comment: In Proceedings UITP 2016, arXiv:1701.0674