# Search for tag: "counterexample"

#### CL - 9a - Recap

This video is a brief recap of most of the logic we have covered so far. You may find it useful, to jog your memory and check your understanding.

From  Haoran Peng on November 2nd, 2020 0 likes 347 plays 0

#### CL - 5x - Supplementary on Sequents

This video includes a couple of points from a 2019 review lecture on Sequents.First we discuss how to use reduction to find an inhabited model in which Γ ⊨ Δ, which is equivalent to…

From  Haoran Peng on October 30th, 2020 0 likes 17 plays 0

#### CL - Sequents

We introduce sequents, where we have finite sets of predicates on both sides of the turnstile.

From  Haoran Peng on October 20th, 2020 0 likes 336 plays 0

#### CL - Lecture 4.j - Reduction 2

We use the rules to reduce a sequent to a conjunction of simple sequents, sequents that only mentions propositional letters, with no connectives, and no repetitions — in this example, we find…

From  Claudia-Elena Chirita on October 15th, 2020 0 likes 341 plays 0

#### CL - Lecture 3d - Using Venn Diagrams to show a Syllogism is Sound

Given a syllogistic rule, how do we show that it is sound? Here we show that using Venn diagrams.

From  Haoran Peng on October 3rd, 2020 0 likes 445 plays 0