Consonant Consonant In articulatory phonetics, a consonant is a speech sound that is articulated with complete or partial closure of the vocal tract. Examples are , pronounced with the lips; , pronounced with the front of the tongue; , pronounced with the back of the tongue; , pronounced in the throat; and , pronounced by forcing air through a narrow channel (fricatives); and and , which have air flowing through the nose (nasals). Contrasting with consonants are vowels. Since the number of possible sounds in all of the world's languages is much greater than the number of letters in any one
Closure with a twist formula_40 and a formula_44 such that formula_45 where formula_46 and formula_47 for all formula_48. Closure with a twist Closure with a twist is a property of subsets of an algebraic structure. A subset formula_1 of an algebraic structure formula_2 is said to exhibit closure with a twist if for every two elements there exists an automorphism formula_4 of formula_2 and an element formula_6 such that where "formula_8" is notation for an operation on formula_2 preserved by formula_4. Two examples of algebraic structures which exhibit closure with a twist are the cwatset and the generalized cwatset, or GC-set. In mathematics, a