Math 2090.03 N Assignment 2
due February 10th, 1999

INSTRUCTIONS: This assignment is due February 10th 1999, in class. Groups may hand in a single assignment paper. The maximum group size is 4.

The assignments must have the name and York number of all group members listed at the top of the paper.

Any axiom may be used. Lower numbered theorems may be used in the proof of a higher numbered theorem.

  1. Give a full dress proof that tex2html_wrap_inline28. You may use Theorems upto and including 3.64.



    By TRANSITIVITY 4 times we have that tex2html_wrap_inline28.

  2. Give a full dress proof of modus ponens (tex2html_wrap_inline34 3.77), i.e. tex2html_wrap_inline36.



    We have that tex2html_wrap_inline40. Leib with E being tex2html_wrap_inline42 gives that tex2html_wrap_inline44. Now tex2html_wrap_inline46, and Sim Subs with p,q:=q,p gives that tex2html_wrap_inline50. Hence by EQUANIMITY we have that tex2html_wrap_inline52.

    So tex2html_wrap_inline52, and tex2html_wrap_inline56, so by EQUANIMITY it follows that tex2html_wrap_inline36.

Stephanie van Willigenburg