The unsolvability of the halting problem turned out to equivalent to a theorem by

In Z₁₀ what is |<2>| ?

What is the largest element in Z₉?

In Z₈ what is |<4>| ?

A complete Graph K_n

The text substitution method originally invented by a Roman emperor is today called

Write the binary numeral 110101 in decimal form

Suppose we have two groups A and B, and there is a mapping F : A → R that is onto but not 1:1, and ∀ a, b ∈ A, F (a * b) = F(a) * F(b). We call F a(n)

Given a graph G with at least one edge, if an edge {u, w} is replaced by a new point v and an edge {u, v} and another edge {v. w} then we have made an elementary ____ of G.

A text assist substitution that uses a different code word each time a message is sent is called a __ system.