I recently received bursts of down votes and deletes of answers written in the past four years (2014 -2017). Discussions on math.meta regarding why my answers were deleted is also deleted on May 13, 2018.

The following answers were deleted:

What is an Empty set?

How are the elementary arithmetics defined?

In Whitehead & Russell's PM, does every Series contain a P1 (immedeately precedes)? (an integral part of an exchange was deleted.)

What does “meaning” mean in Whitehead and Russell's PM?

True Definition of the Real Numbers

A question on Terence Tao's representation of Peano Axioms

Book on foundational reasoning of standard arithmetics “curriculum”

What makes induction a valid proof technique?

Principle of mathematical induction

Peano's Axioms: Mathematical Philosophy

Can multiplication be defined without addition?

Proof that aleph null is the smallest transfinite number?

The following questions & answers were removed without a trace:

1. In Whitehead & Russell's PM, if P is an infinite well-ordered series, can P have a last term? 04Apr18

Please think again before you decide to study "official" mathematics. There is a good chance you will waste your prime time on a huge pile of intellectual rubbish.

In the department of philosophy and mathematics new branches sprout as prolifically as lianas in the rain forest and there is a pullulation of techniques, terms and symbols producing a heterogeneous crop full of chaff that conceals a few kernels of wisdom.

--Hilton, Alice Mary. Logic, Computing Machines, and Automation. Cleveland and New York: Meridian Books, 1964