Predicate that checks if a Clojure vector of two [a b] such that a < b.

Syntax: (interval? [a b]) s.t a, b ∈ ℝ or ℤ

Predicate that checks if a given keyword is in a block.

Syntax: (key-in-block? B :Aij) s.t i, j ∈ ℤ⁺ and i, j ≥ 1

Predicate that returns true if x ∈ {##NaN, ##Inf, ##-Inf}.

Syntax: (not-a-number? x)

Why .equals or identical? over the use of = or == ?

Predicate that checks if a Clojure vector of two [a b] such that a, b > 0.

Syntax: (order? [a b])