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Michał Masny's user avatar
Michał Masny's user avatar
Michał Masny's user avatar
Michał Masny
  • Member for 12 years, 3 months
  • Last seen more than 7 years ago
  • Warsaw, Poland
Profile Activity

17 Questions

Score Activity Newest Views
50 votes
3 answers
11k views

How did "normal" come to mean "perpendicular"?

40 votes
6 answers
5k views

Can one make high-level proofs about chess positions?

15 votes
1 answer
2k views

Automorphisms of $P(\Bbb N)$

15 votes
1 answer
1k views

Is the class of additive groups of rings axiomatizable?

10 votes
1 answer
227 views

Can a semigroup with zero be globally isomorphic to a semigroup without zero?

7 votes
3 answers
516 views

Is the class of inverse semigroups globally determined?

6 votes
2 answers
405 views

For a monoid with zero $M$, how many additive operations on $M$ can there be making $M$ a ring?

6 votes
1 answer
1k views

Who coined "mob" and "clan" and why these words?

5 votes
1 answer
298 views

Sets of natural numbers such that sums of a bounded number of its elements form a semigroup

5 votes
1 answer
216 views

Examples of noncommutative Bezout domains

4 votes
1 answer
407 views

Cancellable elements of a power semigroup

3 votes
0 answers
297 views

Certain conditions on cancellative semigroups

3 votes
0 answers
120 views

dual composition of binary relations

3 votes
2 answers
372 views

How many idempotent relations are there on an $n$-element set?

1 vote
2 answers
356 views

What are the monoids in which every globally idempotent subsemigroup contains the identity element?

0 votes
1 answer
122 views

What are the semigroups in which congruence classes can be multplied like sets?

0 votes
1 answer
377 views

When does a power semigroup have a zero, and what can the zero be?