Logic puzzle might be present in lieu of a grid in a puzzle about the location of different shops. Logic puzzle A logic puzzle is a puzzle deriving from the mathematics field of deduction. The logic puzzle was first produced by Charles Lutwidge Dodgson, who is better known under his pen name Lewis Carroll, the author of "Alice's Adventures in Wonderland". In his book "The Game of Logic" he introduced a game to solve problems such as confirming the conclusion "Some greyhounds are not fat" from the statements "No fat creatures run well" and "Some greyhounds run well". Puzzles like this, where
Logical equivalence Logical equivalence In logic, statements formula_1 and formula_2 are logically equivalent if they have the same logical content. That is, if they have the same truth value in every model (Mendelson 1979:56). The logical equivalence of formula_1 and formula_2 is sometimes expressed as formula_5, formula_6, or formula_7. However, these symbols are also used for material equivalence. Proper interpretation depends on the context. Logical equivalence is different from material equivalence, although the two concepts are closely related. Logical equivalences involving conditional statements： Logical equivalences involving biconditionals： The following statements are logically equivalent: Syntactically, (1) and (2) are derivable from each other