graph 1 2 Sections Graphs Doc

Def member-paren(x,y.E(x;y);i;s) == (xs.InjCase(x; a. E(a;i), E(a;i)))

is mentioned by

Thm* E:(TT). (x,y:T. E(x,y) x = y) (i:T, s:(T+T) List. member-paren(x,y.E(x,y);i;s) (inl(i) s) (inr(i) s))[assert-member-paren]

Try larger context: Graphs

graph 1 2 Sections Graphs Doc