Twenty years ago, cognitive psychologist Elizabeth Spelke took a strong position in an ongoing public debate. "There are no ...

Let A = ⊕α∈ΓAα A = ⊕ α ∈ Γ A α and B = ⊕α∈ΓBα B = ⊕ α ∈ Γ B α be two commutative rings graded by an arbitrary commutative monoid Γ Γ, let J J be a homogeneous ideal of B B and f: A → B f: A → B a ...