The following sorites are taken from Lewis Carroll's Symbolic Logic. All are valid. Rewrite each sorites in standard form, using letters to represent the terms and reducing the number of terms whenever necessary. Then use Venn diagrams or the rules method to prove each one valid.
No interesting poems are unpopular among people of real taste.
No modern poetry is free from affectation.
All your poems are on the subject of soap bubbles.
No affected poetry is popular among people of real taste.
No ancient poem is on the subject of soap bubbles. All your poems are uninteresting.