Operator-irreducible symmetric algebras of operators in the $\mathbf\Pi^1$ Pontryagin space

In this paper we prove that operator-irreducible weakly closed algebras (containing the identity) on $\mathbf\Pi^1$ are reflexive, and construct a canonical model of an arbitrary symmetric operator-irreducible algebra on $\mathbf\Pi^1$ with a bounded norm, which is not (spatially) irreducible.