On Herbrand`s Theorem for Intuitionistic Logic
... to the deducibility of a Herbrand extension, and then the necessary Herbrand terms can be extracted from the cut-free proof. In fact, a similar idea is used in free-variable tableau methods [8], where quantifiers are dealt with separately from dealing with the propositional proof skeleton. Since fre ...
... to the deducibility of a Herbrand extension, and then the necessary Herbrand terms can be extracted from the cut-free proof. In fact, a similar idea is used in free-variable tableau methods [8], where quantifiers are dealt with separately from dealing with the propositional proof skeleton. Since fre ...
Gentzen`s original consistency proof and the Bar Theorem
... in question is obtained by reading the reduction tree, which is constructed ‘bottom-up’, as ‘top-down’. Deduction trees are built up inductively and so proof by induction on them is valid. Moreover, given a deduction tree for a sequent, the corresponding reduction tree can be constructed; but the co ...
... in question is obtained by reading the reduction tree, which is constructed ‘bottom-up’, as ‘top-down’. Deduction trees are built up inductively and so proof by induction on them is valid. Moreover, given a deduction tree for a sequent, the corresponding reduction tree can be constructed; but the co ...
2.1-2.3: Reasoning in Geometry
... Definition of a Vehicle “Anything that has wheels and moves people from place to place.” Not all definitions may be precise, so when creating or following one, read carefully! ...
... Definition of a Vehicle “Anything that has wheels and moves people from place to place.” Not all definitions may be precise, so when creating or following one, read carefully! ...
Chapter 1 Logic and Set Theory
... statement is necessarily true. That is, a proof is a logical argument, not an empirical one. One must demonstrate that a proposition is true in all cases before it is considered a theorem of mathematics. An unproven proposition for which there is some sort of empirical evidence is known as a conject ...
... statement is necessarily true. That is, a proof is a logical argument, not an empirical one. One must demonstrate that a proposition is true in all cases before it is considered a theorem of mathematics. An unproven proposition for which there is some sort of empirical evidence is known as a conject ...
A Paedagogic Example of Cut-Elimination
... tree for F “backwards”. If F is valid, this procedure stops with all leaves of the proof tree being axioms—then we have obtained a proof for F . Otherwise, we can construct a countermodel for F from the tree. For first-order formulas F this tree is in general infinite, but for propositional formulas ...
... tree for F “backwards”. If F is valid, this procedure stops with all leaves of the proof tree being axioms—then we have obtained a proof for F . Otherwise, we can construct a countermodel for F from the tree. For first-order formulas F this tree is in general infinite, but for propositional formulas ...
Lecture slides
... 2. Construct a truth table showing the truth values of all the premises and the conclusion. 3. If the truth table contains a row in which all premises are true and the conclusion is false, then the argument form is invalid. If every case where all premises are true the conclusion is true, then the a ...
... 2. Construct a truth table showing the truth values of all the premises and the conclusion. 3. If the truth table contains a row in which all premises are true and the conclusion is false, then the argument form is invalid. If every case where all premises are true the conclusion is true, then the a ...
Always, Sometimes or Never True - WCER
... The aim of this assessment is to provide the opportunity for you to: test statements to see how far they are true; provide examples or counterexamples to support your conclusions provide convincing arguments or proofs to support your conclusions For each statement, say whether it is always, so ...
... The aim of this assessment is to provide the opportunity for you to: test statements to see how far they are true; provide examples or counterexamples to support your conclusions provide convincing arguments or proofs to support your conclusions For each statement, say whether it is always, so ...
3.3 Inference
... We then used the definition of even numbers, and our previous parenthetic comment suggests that it was natural for us to use the definition symbolically. The definition tells us that if m is an even number, then there exists another integer i such that m = 2i. We combined this with the assumption that ...
... We then used the definition of even numbers, and our previous parenthetic comment suggests that it was natural for us to use the definition symbolically. The definition tells us that if m is an even number, then there exists another integer i such that m = 2i. We combined this with the assumption that ...
Chapter 1 Logic and Set Theory
... be true whenever P is true. That is, Q cannot be false if P is true. Necessity is the key aspect of this sentence, the fact that P and Q both happen to be true cannot be coincidental. To have P implies Q, we need the conditional P → Q to be true under all possible circumstances. Meta-statements, suc ...
... be true whenever P is true. That is, Q cannot be false if P is true. Necessity is the key aspect of this sentence, the fact that P and Q both happen to be true cannot be coincidental. To have P implies Q, we need the conditional P → Q to be true under all possible circumstances. Meta-statements, suc ...
1. Axioms and rules of inference for propositional logic. Suppose T
... For Ass, Ex, Contr and Cut this amounts to the so called “generalized rules of inference” on stated and proved on pp. 91-93 of the coursepack. The rest are a straightforward exercise for the reader making use of associativity. ...
... For Ass, Ex, Contr and Cut this amounts to the so called “generalized rules of inference” on stated and proved on pp. 91-93 of the coursepack. The rest are a straightforward exercise for the reader making use of associativity. ...
Logic Review
... WFF “(B & C),” using the rule →E on lines 2 and 3. But we have only proved (B & C) assuming that 1 and 2 are true. ...
... WFF “(B & C),” using the rule →E on lines 2 and 3. But we have only proved (B & C) assuming that 1 and 2 are true. ...
PPT
... Many theorems in mathematics have the form of an implication PQ, where one assumes the validity of P , then with the aid of existing mathematical facts and theorems as well as laws of logic and reasoning, arrive at the conclusion Q. Although the goal is always to “go from P to Q,” is more than one ...
... Many theorems in mathematics have the form of an implication PQ, where one assumes the validity of P , then with the aid of existing mathematical facts and theorems as well as laws of logic and reasoning, arrive at the conclusion Q. Although the goal is always to “go from P to Q,” is more than one ...
The Foundations: Logic and Proofs
... Let p be “I will study discrete math.” Let r be “I will study English literature.” Let q be “I will study databases.” “I will not study discrete math or I will study English literature.” “I will study discrete math or I will study databases.” “Therefore, I will study databases or I will English lite ...
... Let p be “I will study discrete math.” Let r be “I will study English literature.” Let q be “I will study databases.” “I will not study discrete math or I will study English literature.” “I will study discrete math or I will study databases.” “Therefore, I will study databases or I will English lite ...