Math 2090.03 N Assignment 3
due March 5th, 1999

INSTRUCTIONS: This assignment is due March 5th 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_inline14 (tex2html_wrap_inline16 3.76 d)) using proof technique 4.1.
  2. Give a full dress proof of modus ponens (tex2html_wrap_inline16 3.77), i.e. tex2html_wrap_inline20 using the Deduction Theorem (4.4).
  3. Give a full dress proof that tex2html_wrap_inline22 using Proof by Cases (4.5). You are allowed to use theorems upto and including Theorem 3.40.

Stephanie van Willigenburg