unforum  a.r.g.b.b    Calendar    FAQ    Search    Memberlist    Usergroups    Register    Log in    Welcome! New users, PLEASE read these forum guidelines. New posters, SEARCH before posting and read these rules before posting your killer new campaign. New players may also wish to peruse the ARG Player Tutorial. All users must abide by the Terms of Service. This week sponsored by: amandel! Why do we need your help? Announcements Having Trouble with the Boards? Ask in the General Forum or email unforum /at/ unfiction.com Our Esteemed Contributors   The time now is Mon May 20, 2013 7:55 am All times are UTC - 6 View posts in this forum since last visit View unanswered posts in this forum Calendar  Calendar Sun 19 May 2013 Mon 20 May 2013 Tue 21 May 2013 Wed 22 May 2013 Thu 23 May 2013 Fri 24 May 2013 Sat 25 May 2013  Forum index » Diversions » Perplex City Puzzle Cards » PXC: Black Puzzle Cards [Black maze set] #216 Formal logic Post a reply     Username Confirmation code Subject Subject description Message icons No icon Message body Emoticons View more Emoticons  Font colour: Default Dark Red Red Orange Brown Yellow Green Olive Cyan Blue Dark Blue Indigo Violet White Black  Font size: Font size Tiny Small Normal Large Huge Close Tags [quote="locqust"]Card worth 54 points Puzzle by Andrew McCarthy Text says..... [u]Key [/u] '(upside down capital A)' Corresponds roughly to the English word 'every' '(back to front capital E)' Corresponds roughly to the English word 'some' The variables x,y,z range over objects. '_ -> _ ' Corresponds roughly to the English phrase 'if_then_'. [u]Question one[/u] Which of the following formalises the claim that every person has a common ancestor (where 'P' = '_is a person' and 'A' = 'is an ancestor of _ _'). (i) ((back to front capital E)x)((upside down capital A)y)(P(y) -> A(xy)) (ii) ((upside down capital A)x)((back to front capital E)y)(P(x) -> A(yx)) (iii) ((upside down capital A)x)(P(x) -> A(xx)) [u]Question 2[/u] What is the name of the paradox that is represented here in the following set-theoretic notation. R={x : x (euro sign) x} i) Sorities paradox ii) Cantor's paradox iii) Russell's paradox end of text.[/quote] Options HTML is ON BBCode is ON Smilies are ON Disable HTML in this post Disable BBCode in this post Disable Smilies in this post  Forum index » Diversions » Perplex City Puzzle Cards » PXC: Black Puzzle Cards Topic review Back to top Like this site and want to support it? Powered by phpBB © 2001, 2005 phpBB Group