• INDEPENDENT -SET = {[G, k] : G is an undirected graph with an independent set of vertices I ⊆ V (G) of size ≥ k} where a subset I is independent iff it contains no edges of G. – Guess a set I of size k. Verify that it contains no edges of G. • CLIQUE = {[G, k] : G is an undirected graph with an independent set of vertices C ⊆ V (G) of size ≥ k} where a subset C is a clique iff every edge on t...

L = {x such that x is an acceptable Riemann Hypothesis proof} is in NP and therefore, using a reduction, we can come up with a circuit C that takes as input x and outputs 1 if x is a proof for the Riemann Hypothesis or 0 otherwise. Our goal now is to design a pair of PPT machines (Enc,Dec) such that: 1. Enc(C,m) takes as input the circuit C and m ∈ {0, 1} and outputs a ciphertext e ∈ {0, 1}∗. 2...

Monotone 3-Sat-4 is a variant of the satisfiability problem for boolean formulae in conjunctive normal form. In this variant, each clause contains exactly three literals—either all or none of them are positive, i. e., no clause contains both a positive and a negative literal—and every variable appears at most four times in the formula. Moreover, every clause consists of three distinct literals....

One of the central questions in topology is determining whether a given curve is knotted or unknotted. An algorithm to decide this question was given by Haken in 1961, using the technique of normal surfaces. These surfaces are rigid, discretized surfaces, well suited for algorithmic analysis. Any oriented surface without boundary can be obtained from a sphere by adding “handles”. The number of ...