Polynomial time algorithm - first order query, Mathematics

Assignment Help:

For queries Q1 and Q2, we say Q1 is contained in Q2, denoted Q1 ⊆ Q2, iff Q1 (D) ⊆ Q2(D) for every database D.

  • The container problem for a fixed Query Q0 is the following decision problem: Given a query Q, decide whether Q0 ⊆ Q.
  • The containee problem for a fixed query Q0 is the following decision problem: Given a query Q, decide whether Q ⊆ Q0.

Formally prove or disprove the following statements:

(a) For every conjunctive query Q0, there is a polynomial-time algorithm to decide the container problem for Q0 and for given conjunctive queries Q.

(b) For every conjunctive query Q0, there is a polynomial-time algorithm to decide the container problem for Q0 and for given conjunctive queries Q that can be obtained from Q0 by adding some atoms.

(c) For every conjunctive query Q0, there is a polynomial-time algorithm to decide the containee problem for Q0 and for given conjunctive queries Q.

(d) For every first-order Query Q0, there is an algorithm to decide the containee problem for Q0 and for given first-order queries Q. To prove a statement, sketch an algorithm, along with an argument why it is polynomial, if possible. To disprove it, provide an M-hardness or undecidability proof.


Related Discussions:- Polynomial time algorithm - first order query

The square of a positive number is 49 what is the number, The square of a p...

The square of a positive number is 49. What is the number? Let x = the number.  The sentence that is , "The square of a positive number is 49," translates to the equation x 2

Multiply two radicals, Multiply following.  Assume that x is positive. ...

Multiply following.  Assume that x is positive.                  (3√x-√y)(2√x-5√y)   Solution                 (3√x-√y)(2√x-5√y)          =6√x 2 -15√x√y-2√x√y+5√y

Derive expressions for the mean and variance, On each day t of n days, N cu...

On each day t of n days, N customers of a supermarket were sampled and the number Xt expressing dissatisfaction was recorded. The results suggested that there were good and bad day

Example of linear equations, Example of Linear Equations: Solve the eq...

Example of Linear Equations: Solve the equation 2x + 9 = 3(x + 4). Solution: Step 1. Using Axiom 2, subtract 3x and 9 from both sides of the equation. 2x + 9 = 3(

Example of inverse matrix, Determine the inverse of the following matrix, i...

Determine the inverse of the following matrix, if it exists. We first form the new matrix through tacking onto the 3 x 3 identity matrix to this matrix.  It is, We

Mensuration, if area of a rectangle is 27 sqmtr and it perimeter is 24 m fi...

if area of a rectangle is 27 sqmtr and it perimeter is 24 m find the length and breath#

Find the perimeter of the rectangle, Find the perimeter of the figure, wher...

Find the perimeter of the figure, where AED is a semi-circle and ABCD is a rectangle.    (Ans : 76cm) Ans:    Perimeter of the fig = 20 + 14 + 20 + length of the arc (AED

Determine the ratio in which the line 2x + y -4 = 0, Determine the ratio in...

Determine the ratio in which the line 2x + y -4 = 0 divide the line segment joining the points A (2,-2) and B (3, 7).Also find the coordinates of the point of division. [Ans:2 :

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd